Turnover like that can kill an offense for a year or two. Yes, he already played under Beck's offense and performed well against bad teams, but football is a team sport. The rest of the offense (focus on the O-line) will be learning a new offensive scheme. They are losing a lot of players to the portal and they'll have to bring in a lot of new players - players who might have experience in other P5 programs, but not Beck's offense.
I guess what I'm saying is that it might not matter next year who they have playing on offense - it could get really ugly, real fast for them. It's going to take a while to get that offense clicking and on the same page. Especially where they struggled so badly this last year, with very little turnover in the ranks.
Utes need to realize that he won't be putting up those numbers at Utah next year, even IF he stays healthy. I predict it will be another tough year for the Ute offense and the fans will turn on Beck and the other BYU coaching staff pretty early in the season.