Kain Colter was undeterred after his first effort to speak up on behalf of college football players led to an uncomfortable moment.

Northwestern's starting quarterback and co-captain gained national attention for scrawling "A.P.U." — for "All Players United" — on his wristbands and towel during the Wildcats' Sept. 21 game against Maine.

While explaining his reasoning to reporters, Colter was interrupted by NU coach Pat Fitzgerald, who hollered from a nearby practice field. Fitzgerald warned media members that if they wanted to ask him questions after practice, they would have only "three minutes" remaining with Colter.

Fitzgerald later said he was "100 percent" behind Colter but that he wanted the protest to be in a "team structure" with everyone participating.

Colter said at the time that "a handful" of NU players had written the initials on their gear but declined to name them. It was not clear on television replays who else participated.

Fitzgerald, Colter said at the time, "felt a little blindsided by it. But in my perspective … the whole APU thing goes against having to ask permission to voice our opinions."

Colter's season was cut short by a shoulder stinger and slowed by a week-one concussion at Cal and an ankle injury suffered in practice before the Wisconsin game.

"It hurt throughout the season and I got a few shots," Colter said. "It never really got better."

Colter still did well last week as a receiver during Senior Bowl practices, likely improving his NFL draft stock. But he left Mobile, Ala., before the game to undergo ankle surgery and hopes to recover in time to participate in NU's Pro Day on March 4.

Asked how his involvement to unionize college football players will influence his draft stock, Colter replied: "It's hard to say. I hope the coaches and execs see that I will fight for my teammates, and hopefully they had nieces and nephews who played college sports and can relate to some of the pitfalls of the NCAA. We're trying to make the experience better."