Adrian Martinez had a pretty good college debut on Saturday as the first true freshman to start the opener at quarterback in Nebraska’s long program history.

But the ending might be one that Big Red Nation replays for a while. We simply don’t know yet.

Martinez was 15-of-20 passing for 187 yards, one touchdown and one interception in Saturday’s 33-28 loss at home against Colorado. The freshman also led the Cornhuskers in rushing with 15 carries for 117 yards (a 7.8-yard average) and two touchdowns.

But one play near the end of the game soured the entire experience for Nebraska fans.

Martinez was hit in the right knee while he was trying to find a receiver in the pocket. He went down with 3:29 left in the game and did not return after this play:

Sophomore walk-on quarterback Andrew Bunch — like Martinez, a native Californian — entered in relief and played Nebraska’s final two offensive drives. But between those possessions, the Buffaloes drove 77 yards on seven plays to score the go-ahead touchdown. Bunch did a few things well but he had five incompletions, as many as Martinez had all game.

Here is the big problem for Nebraska: The Cornhuskers have very little depth at quarterback.┬áIf Martinez is seriously hurt — and again, that is not certain — then they are down to two available QBs listed on the roster. Bunch is a walk-on and Matt Masker is another freshman. The fourth quarterback on the roster, Noah Vedral, came with coach Scott Frost from UCF and is sitting out this season because of NCAA transfer rules.

Nebraska had a quarterback derby in the fall between Martinez and Tristan Gebbia, a redshirt freshman. Gebbia could have been the one to step in on Saturday against Colorado, but when he lost the race to be the starter he transferred to Oregon State, where he is sitting out and will have to wait until the 2019 season to compete for the starter’s job.

Quite a bit rides on Martinez’s health going forward for the Cornhuskers. If he is out for an extended period, Nebraska’s fans, coaches and players might start reliving the bad memories of last season’s 4-8 campaign.