Oklahoma State joins Arkansas State and Massachusetts as the first three schools to offer the Charleston (Ark.) High standout, who could play either side of the ball in college as a receive or a safety.
"OSU was a great place and everyone has great energy and was friendly," Flanagan said. "The players had a great energy about them and were hyped up for their Orange and Black game. We only visited the football facilities, but based off of that it seems like a great place."
Flanagan said he felt welcome and comfortable during his visit, which marked his first trip to Stillwater.
"The way everyone gets along and had good energy kind of stood out to me," Flanagan said. "I guess it stood out because that's how you want to feel on a visit. Not intimidated or scared to be there."
While the 6-foot-1, 181-pound Flanagan, who ran an impressive laser-timed 4.64 40 in mid-March at The Opening New Orleans, can play either side of the ball, Oklahoma State wants him for defense.
"I spent the most time with coach Hammer," said Flanagan, referring to safeties coach Dan Hammerschmidt. "He told me that from what he saw on film I fit the bill perfectly. Coach Hammer plans to use me as the free safety or nickel back because of their fast, aggressive defense.
"OSU as of right now is my No. 1 choice to play football. For visits to other schools, I will keep my options open and listen to what they have to offer."
The spring evaluation period, which runs from April 17 through May 31, should provide more recruiting attention for Flanagan, especially now that he owns a P5 offer from the Cowboys.
For now, Flanagan said he will concentrate on preparing for his senior season.
"This offseason I've been trying to put on weight and get stronger," Flanagan said. "My speed has stayed around the same for a while now, but I have gained weight and my lift maxes have gone way up."