Less than one year after arriving at Wisconsin as the team's starting quarterback, O'Brien confirmed to Badger Nation that he is leaving the program.
O'Brien made the decision after it became clear following a meeting with head coach Gary Andersen that he wasn't going to get an opportunity to earn the starting job in fall camp; a competition that looks to be a three-way battle between sixth-year senior Curt Phillips and redshirt sophomores Tanner McEvoy and Joel Stave.
During spring practices, O'Brien was rarely used during scrimmages and in the spring game. He went 0 for 3 in his only series of action with the Badgers' second team during the final spring practice.
"Coach Andersen has been awesome with helping me out," O'Brien said exclusively to Badger Nation. "I wanted to stay and I basically asked (Andersen) if I was going to get a chance to compete in the fall. He just said he couldn't guarantee that and it would be similar to spring, which I didn't get a chance to really compete. And that's fine. I am thankful because if that's going to be the case I want to play somewhere for my last year.
"Coach Andersen has been extremely supportive in guiding me through it."
Transferring to Wisconsin in May 2012 under the graduate transfer exception rule and earning the Badgers' starting quarterback job with a strong showing during fall practices, O'Brien got fans' excited about the offense's potential after the first week, completing 19 of 23 passes for 219 yards and two touchdowns during a victory against Northern Iowa.
Unfortunately everything went downhill after that. O'Brien fumbled twice and lost one in Wisconsin's surprisingly week-two loss at Oregon State and struggled to move the ball in week three against Utah State, prompting then-Badgers coach Bret Bielema to replace him with quarterback Joel Stave at halftime.
O'Brien didn't start another game, and made only four more appearances the rest of the season. He finished the season completing 52 of 86 passes (60.5 percent) for 523 yards with three touchdowns and one interception. He fumbled five times and lost three of them.
"I made a lot of great friends and exchanging a lot of texts and phone calls today with a lot of them was great," said O'Brien. "A lot of those guys I will remain friends with for the rest of my life. It was an honor to play with them and be their teammate. Obviously the football part didn't work out like it was supposed to, but I have no regrets about anything."
As a redshirt freshman at Maryland in 2010, O'Brien was voted the ACC Rookie of the Year, becoming the first player in program history to earn the honor, throwing for 2,438 yards with 22 touchdowns and eight interceptions in 10 starts.
But a coaching and offensively philosophy change in O'Brien's sophomore season made the quarterback look for a school with a traditional pro-style offense instead of using the spread.
That brought him to Wisconsin, but O'Brien could never get comfortable with an offensive going through massive transitions on and off the field during the nonconference portion of the schedule.
"Transition was probably a key work, whether it be with coaches, players of the system or whatever, but that's not for me to say why it didn't work out," said O'Brien. "I worked my butt off every day. I would like to think I earned the respect of the guys there. There can only be one quarterback on the field.
"I've been on the good and bad side of playing quarterback. You win and you get more of the praise you probably deserve. You lose and you get more of the blame than you probably deserve. That's the nature of it and I except it.
"I am just excited for the opportunity to play next year, put a year's worth of film on tape and see what happens."
Given his full release, O'Brien hopes to have a final decision made in the next few weeks, and will be playing for his fifth head coach in four seasons.