Hill will have surgery within seven days, and recovery time is expected to be 4-6 months. Mendenhall said senior Riley Nelson was on track from his recovery from a back injury to play against Oregon State on Saturday (1:30 p.m., ABC) and will start at quarterback.
Hurst said it is unknown whether Hill will be able to participate in spring ball next March, saying Hill has some "ligamentus and muscular structures that need to be repaired, and then recover."
The first-year head trainer said LCL injuries are "a little bit less significant as far as time goes [for recovery] than an ACL injury," which requires 6-10 months of recovery time.
Doman, the second-year OC, said before the play that Hill was injured on he told the freshman to let the clock run down, but Hill "misinterpreted" that to mean he should run a play.
Mendenhall said the sideline coaches gave a rolling hand signal to Hill to let him know the clock was running, but Hill thought that meant to continue to run the play. When they realized he was going to run a play, they gave him the "victory formation signal," but Hill had turned his head.
At that point, Mendenhall and Doman said, they wanted to call a timeout, but the play had started.
"Once I saw him not look back ... I was trying to do anything to get to that point" of calling a timeout, Mendenhall said.
Said Doman: "It is my fault, at least that's how I feel. I'm responsible for that, and I don't know that I will ever get over him getting injured the way that he did."
Saturday's opponent, Oregon State, also is dealing with a heartbreaking quarterback injury. Starter Sean Mannion suffered a left knee injury that will require surgery in the 19-6 win over Washington State and is out indefinitely.
As for BYU's Nelson, who started the Cougars' first four games of the season, he took all the reps at practice Monday and said his arm strength has returned, but his conditioning level is lacking a bit.
"But as far as feeling physically good and walking around in every day life, yeah, 100 percent," he said.