Don’t be surprised if you see Trent Williams alternating with Jaylon Moore on Monday.

Williams, the 49ers’ left tackle, just signed a contract extension with the team last week, but after missing all of training camp. If he is unable to participate, that would mean Jalen Moore would be the 49ers’ left tackle.

Could Trent Williams’ conditioning be in question? Chris Foerster, the 49ers’ offensive line coach and run game coordinator, hinted at that possibility.

“I intentionally tried to have Jalen only represent the left side,” Foerster said in his press conference on Friday. “Because I don’t know.”

Foerster brought up the 2020 COVID-19 season in a game against the Los Angeles Rams. The 49ers offense had a high number of plays, a situation in which Williams told Foerster he would “hang in there.”

“Will there be a rotation?” Foerster said. “I don’t know. We’ll see how Trent does after tomorrow (Saturday) and what exactly happens. Hopefully Trent can pull it off. If not, Jalen definitely had a good training camp and is ready to go.”

Foerster made it clear that it’s possible we could see Moore for at least one series to give Williams a breather.

On Saturday, Kyle Shanahan echoed Foerster’s comments. While Williams has improved day by day, Shanahan has a “we’ll see” attitude.

“You have to pay attention, you have to talk to them,” Shanahan said. “I haven’t done that much with a tackle. O-linemen are different in terms of rotation and sort of skill positions. It’s also weird to see Trent just sitting next to us on the sideline.”

Jaylon Moore had a somewhat shaky preseason to begin with, but so did the entire 49ers offensive line. He looked much, much better in his last few preseason games when more first-team players were on the field. He’s no Trent Williams, but it could be worse. After all, it could be Zane Beadles.

“He (Trent Williams) will be honest with us about how he feels and I know Chris (Foerster) will be watching that very closely.”