Clay has spent nearly a half-century coaching football and has served as defensive coordinator at seven Division I schools, including Oklahoma State from 2001-04. Wyatt is another former Oklahoma State assistant (2001) who has served as offensive coordinator at Kansas and Southern Mississippi and co-offensive coordinator at Kansas and Texas.
"Today is a really encouraging day for Oklahoma State football. We have five great additions to our staff who bring a wealth of knowledge and experience in the game," Gundy said. "I want to thank Coach Holder for his patience and for the tireless work he has put in with me the past few weeks as we have worked on this together."
A closer look at each member of the staff:
? Greg Adkins spent the last two seasons in the National Football League coaching tight ends for the Buffalo Bills.
? Prior to joining the staff at Oklahoma State, he had 24 years of coaching experience, with eight of those coming in the Southeastern Conference.
? He got his start at Marshall coaching the defensive line, tight ends and offensive line from 1991-95 before moving on to Georgia in 1996 to coach the Bulldogs' defensive line.
? One season later, he switched to the offensive side of the ball, where he mentored UGA's offensive line and tight ends from 1997-2000. A two-year stint coaching offensive line and serving as recruiting coordinator at Troy from 2001-02 was followed by a six-year run at Tennessee, where he coached tight ends and offensive line and served as the Volunteers' recruiting coordinator.
? He moved on to Syracuse in 2009 to coach offensive line and serve as recruiting coordinator before head coach Doug Marrone from Syracuse to the Buffalo Bills.
? Among the numerous notable players he either coached or recruited are Champ Bailey and Boss Bailey at Georgia, DeMarcus Ware at Troy and Erik Ainge at Tennessee.
? Coached three Syracuse offensive linemen to NFL opportunities (Ryan Bartholomew, Andrew Tiller and Michael Hay), plus a fourth offensive lineman - Justin Pugh - to a college career in which he earned All-Big East accolades three times.
? He helped coach Syracuse to a win in the 2010 New Era Pinstripe Bowl. It was the first bowl trip for the Orange in six years and marked SU's first bowl win in nine seasons.
? Adkins helped coach Tennessee to prominent bowl games to cap the 2003, 2004, 2006 and 2007 seasons. In 2007, his offensive line paved the way for a Volunteer offense that produced a 3,000-yard passer (Erik Ainge), a 1,000-yard rusher (Arian Foster) and a 1,000-yard receiver (Lucas Taylor).
? In 2007, Tennessee's offensive line led the nation by allowing only four sacks. Those four sacks came on 534 pass attempts (one sack per 133.5 pass attempts - a mark that also led the nation).
? His offensive line at Georgia led the way for players such as Hines Ward and Robert Edwards. In 1997, the Bulldogs went 10-2 and finished the season ranked No. 10 in the Associated Press poll. UGA won no fewer than eight games in each of his final four seasons in Athens.
? Adkins enjoyed outstanding success during his time at Marshall, helping coach his alma mater to the 1992 national championship and four trips to the national title game in a five-year span from 1991-95. With Adkins as defensive line coach, the Thundering Herd led the Southern Conference in rush defense in 1992. He moved to the offensive side of the ball in 1993 and Marshall went on to lead the league in scoring offense from 1993-95.
? A 1990 graduate of Marshall University with a degree in sports management and marketing, Adkins was a four-year letterman for the Thundering Herd and served as team captain his senior year. During his 10 years at Marshall, both as a player and as a coach, he was part of 97 victories.
Personal ? Adkins and his wife, Michelle, have two sons, Nicholas and Nathan, and a daughter, Natalie.
1991-95: Marshall - Defensive Line/Tight Ends/Offensive Line
1996: Georgia - Defensive Line
1997-2000: Georgia - Offensive Line/Tight Ends
2001-02: Troy - Offensive Line/Recruiting Coordinator
2003-05: Tennessee - Tight Ends/Assistant Offensive Line/Recruiting Coordinator
2006-08: Tennessee - Offensive Line
2009-12: Syracuse - Offensive Line/Recruiting Coordinator
2013-14: Buffalo Bills - Tight Ends
1991 Division IAA National Championship game
1992 Division IAA National Champions
1993 Division IAA National Championship game
1994 Division IAA Playoffs
1995 Division IAA National Championship game
1998 Outback Bowl
1998 Peach Bowl
2000 Outback Bowl
2000 Oahu Bowl
2004 Peach Bowl
2005 Cotton Bowl
2007 Outback Bowl
2008 Outback Bowl
2010 New Era Pinstripe Bowl
Ryan Bartholomew, Arizona Cardinals
Andrew Tiller, New Orleans Saints
Michael Hay, St. Louis Rams
Arron Sears, Tampa Bay Buccaneers
Anthony Parker, Second-team All-American at Tennessee
Michael Munoz, Draddy Trophy winner at Tennessee
Chris Scott, Pittsburgh Steelers
Ramon Foster, Pittsburgh Steelers
Recruited DeMarcus Ware, Dallas Cowboys
Recruited Champ Bailey, Denver Broncos
Will Witherspoon, St. Louis Rams
Jon Stinchcomb, New Orleans Saints
Ben Watson, New England Patriots
Randy McMichael, St. Louis Rams
George Foster, Detroit Lions
Jermaine Wiggins, Minnesota Vikings
Jason Ferguson, Miami Dolphins
Jermaine Smith, Green Bay Packers
Jason Rader, Atlanta Falcons
? Marcus Arroyo spent last season as quarterbacks coach for the Tampa Bay Buccaneers. After a health procedure sidelined Bucs offensive coordinator Jeff Tedford, Arroyo was thrust into the role of Tampa Bay's play caller.
? Arroyo came to Tampa Bay following one season (2013) as the offensive coordinator and outside receivers coach at Southern Mississippi, where his primary duties included creating the offensive game plans and play calling on game day.
? Prior to joining the Southern Mississippi coaching staff, Arroyo spent two years (2011-2012) at the University of California as the passing game coordinator.
? Under Arroyo's guidance, Cal quarterback Zach Maynard worked himself into the No. 10 spot on the career list at the school in both passing yards (5,204) and total offense (5,350) in only two seasons. His 128.36 career passer efficiency rating is eighth on the school's all-time list.
? Cal had a much improved offense in 2011 during Arroyo's first-year of working with the team's quarterbacks, especially in the passing game where the Golden Bears jumped from No. 94 in the country in 2010 (175.08 ypg) to No. 46 in the country in 2011 (246.62 ypg).
? Cal also rose from No. 90 nationally (334.00 ypg) to No. 44 nationally (401.46 ypg) in total offense in his first season. In addition, Cal moved up 20 spots to No. 53 nationally in scoring, improving from 25.8 points per game the previous season to 28.3.
? Before coaching at California, Arroyo served for two seasons at Wyoming as offensive coordinator and quarterbacks' coach during the 2009 and 2010 campaigns. He helped develop 2009 true freshman quarterback Austyn Carta-Samuels into the Mountain West Conference Freshman of the Year and the Offensive MVP of the 2009 New Mexico Bowl. Carta-Samuels completed 59.7 percent of his passes in two campaigns under Arroyo's guidance.
? Arroyo made a significant impact in his first season at Wyoming in 2009 when he installed a new spread offense that helped the Cowboys score 30 or more points five times, winning all five of those games. Arroyo's offense displayed an ability to come from behind in his first season, recording five fourth-quarter comebacks. His offensive unit also did an outstanding job of protecting the ball. Wyoming ranked No. 7 in the nation in fewest turnovers lost (14) and was No. 15 nationally in both fewest fumbles lost (7) and fewest interceptions thrown (7).
? When Wyoming captured the 2009 New Mexico Bowl title, it marked the second time in four seasons that Arroyo was part of a New Mexico Bowl winning team. His other victory in the game came in 2006 while he was coaching at San Jose State.
? Prior to his stint at Wyoming, Arroyo was the co-offensive coordinator for two seasons and quarterbacks coach for three campaigns at his alma mater, San Jose State. He was the quarterbacks' coach and play-caller for the Spartans in 2006, before being promoted to co-offensive coordinator for his final two seasons in 2007 and 2008 under head coach Dick Tomey.
? From 2006-07, Arroyo tutored the Spartans' all-time leading passer and total offense leader Adam Tafralis, who set school records for career passing yards (7,548) and total offense (8,111). Tafralis went on to sign a free agent contract with the Indianapolis Colts of the NFL in the spring of 2008. He also played three seasons (2008-10) with the Hamilton Tiger-Cats of the Canadian Football League, and spent time on the rosters of both the United Football League's Sacramento Mountain Lions (2011) and the CFL's Toronto Argonauts (2012) before his retirement from football.
? Arroyo also spent one season at San Jose State in 2005 as a graduate assistant coach on the offensive side of the ball before being elevated to a full-time assistant in 2006.
? Arroyo began his collegiate coaching career in 2003, serving as an undergraduate assistant coach at his alma mater for one year. In 2004, he was the offensive coordinator at Prairie View A&M, an NCAA Division I Football Championship Subdivision (FCS) team in Prairie View, Texas.
? A native of Sacramento, Calif., Arroyo was a three-year letterman at San Jose State, where he played quarterback from 1998-2002. In 2000, he passed for 2,334 yards and 15 touchdowns. He led the Spartans to seven wins that season, which was the most they had compiled in eight seasons.
? Arroyo graduated with a degree in kinesiology from San Jose State.
Personal ? He and his wife, Kelly, were married on July 9, 2010. Kelly began her collegiate athletic career as a volleyball player at Southern Oregon and later was a swimmer at San Jose State.
2003: San Jose State - Undergraduate Assistant
2004: Prairie View A&M - Offensive Coordinator
2005: San Jose State - Offensive Graduate Assistant
2006: San Jose State - Quarterbacks Coach/Play-Caller
2007-08: San Jose State - Co-Offensive Coordinator/Quarterbacks Coach
2009-10: Wyoming - Offensive Coordinator/Quarterbacks Coach
2011-12: California - Passing Game Coordinator/Quarterbacks Coach
2013: Southern Mississippi - Offensive Coordinator/Outside Receivers Coach
2014: Tampa Bay Buccaneers - Quarterbacks Coach
2006 New Mexico Bowl
2009 New Mexico Bowl
2011 Holiday Bowl
? The 2011 American Football Coaches Association FCS Assistant Coach of the Year, Jason McEndoo spent 12 seasons as an assistant coach at Montana State prior to coming to Oklahoma State. His 12 years at Montana State make him the longest-tenured assistant coach in Bobcat football history.
? McEndoo helped coach Montana State to five Big Sky Conference championships during his time in Bozeman.
? In 2014, Montana State ranked seventh among all FCS schools with 244.4 rushing yards per game, was ninth in the FCS with 488.6 yards of total offense per game and was 11th in the FCS with 38.2 points per game.
? McEndoo coached seven Bobcat All-Americans and 11 first team All-Big Sky selections, including Jeff Bolton, an All-America center who earned the 2005 Rimington Award as Division I-AA's top player at that position.
? He also coached 2010 consensus All-America Mike Person (a seventh round choice by San Francisco in the 2011 NFL Draft), and 2012 first-team All-Big Sky and Honorable Mention All-America choice Shaun Sampson.
? In 2011, two Bobcat O-linemen - Conrad Burbank and Alex Terrien - earned All-America honors.
? MSU's offensive front led the Big Sky in fewest sacks allowed in 2006 and 2008, and the Bobcats led the league in rushing yards in 2008.
? Under McEndoo's guidance, the offensive line was a leadership hub in the Bobcat program. At least one offensive lineman served as a team captain in 10 of McEndoo's 12 seasons.
? A native of Aberdeen, Wash., McEndoo was an offensive lineman at Washington State and earned All-Pac 10 honors in 1997. He graduated from Wazzu in 1998, then spent three seasons in the NFL with the Seattle Seahawks and New Orleans Saints. He finished out a master's degree from Whitworth in 2003.
? He coached high school football in Washington from 2000-02 before arriving at MSU in 2003.
? McEndoo and his wife, Ruth, have a son, Luke, and three daughters - Elizabeth, Aubrie and Ainslee.
2000-01: Lake Washington HS - Offensive Line
2002: Mt Spokane HS - Offensive Line
2003-14: Montana State - Offensive Line
1969-71: Virginia - Assistant Coach
1972: Virginia Tech - Linebackers
1973-74: South Carolina - Linebackers
1976-79: Southern Mississippi - Assistant Coach
1980-81: Southern Mississippi - Defensive Coordinator
1982-86: SMU - Defensive Coordinator
1987: Tampa Bay Buccaneers - Defensive Assistant
1988: Temple - Defensive Coordinator
1989-90: Mississippi State - Assistant Coach
1991-95: Mississippi State - Defensive Coordinator
1996: UTEP - Defensive Coordinator
1997-2000: UAB - Defensive Coordinator/Linebackers
2001-04: Oklahoma State - Defensive Coordinator
2005: Louisiana Tech - Inside Linebackers
2006-07: Texas A&M - Safeties
2008-10: Samford - Linebackers
2011: Blinn College - Defensive Coordinator
1980 Independence Bowl
1981 Tangerine Bowl
1982 Cotton Bowl
1983 Sun Bowl
1984 Aloha Bowl
1991 Liberty Bowl
1993 Peach Bowl
1994 Peach Bowl
2002 Houston Bowl
2003 Cotton Bowl
2004 Alamo Bowl
2006 Holiday Bowl
1989-91: Trinity Valley CC - Wide Receivers/Defensive Backs>
1992-94: Sam Houston State - Wide Receivers
1995: Wyoming - Wide Receivers
1996: Baylor - Wide Receivers
1997: Kansas - Wide Receivers
1998-99: Kansas - Assistant Head Coach/Wide Receivers
2000: Kansas - Associate Head Coach/Offensive Coordinator/Wide Receivers
2001: Oklahoma State - Passing Game Coordinator/Wide Receivers
2002-04: Oklahoma - Wide Receivers
2005: Oklahoma - Passing Game Coordinator/Wide Receivers
2006: Minnesota Vikings - Wide Receivers
2007: Arizona - Passing Game Coordinator/Wide Receivers
2008-09: Southern Mississippi - Associate Head Coach/Offensive Coordinator/Wide Receivers
2010: Kansas - Co-Offensive Coordinator/Wide Receivers
2011-12: Texas - Co-Recruiting Coordinator/Wide Receivers
2013: Texas - Co-Offensive Coordinator/Wide Receivers
2013 Alamo Bowl
2012 Alamo Bowl
2011 Holiday Bowl
2009 New Orleans Bowl
2008 New Orleans Bowl
2005 Holiday Bowl
2005 Orange Bowl
2004 Sugar Bowl
2003 Rose Bowl