Kyle Shanahan assesses the play of Trey Lance, Trey Sermon, others during 49ers-Seahawks

Kyle Shanahan had a chance to study the film from yesterday's disappointing loss to the Seattle Seahawks and has reviewed the game with his players. The San Francisco 49ers head coach spoke with reporters today via a conference call and assessed the play of several players, including rookie quarterback Trey Lance.

Lance started the second half after Jimmy Garoppolo sustained a calf contusion. The veteran quarterback will be re-evaluated later this week and could still play against the Arizona Cardinals on Sunday.

As for Lance, he finished the game 9-of-18 for 157 yards with two touchdowns. The coach was asked what teaching points from the game he touched on his with his rookie quarterback.

"There's stuff on every play that we talk about, but just in general, I was talking to him about how he felt in there," Shanahan said. "You always picture your first NFL game and when you got to go in there, and I know he's been in for some plays, but not really to do every single play like that. And just getting in and out of the huddle, being with the guys, I think he enjoyed the moment.

"I thought he did a good job making some plays, especially when some weren't there with his feet. A couple of passes I know he'd like to have back, but it was really just getting that experience, and talking to him about how it was, and all the things that can happen on each one of those plays, and how it pertains [to] the next week too."

Lance has a chance to start his first NFL game this weekend. Shanahan says the quarterback's mentality is to approach every week like he expects to start.

"But this is the first week going into it that he's legitimately got up a chance to on the first play," Shanahan added. "So, he's got to approach it that way, learn from the stuff that he did last night, and come in ready to go on Wednesday."

Rookie running back Trey Sermon saw his most extensive action of the season, carrying the ball 19 times for 89 rushing yards (4.7 yards per carry).

"I thought he took a step in the right direction," Shanahan said. "I thought, like I kind of said with the whole run game, I thought he was better this week than he was the week before. But, I still know there's another level for him."

Left tackle Trent Williams left the game with a shoulder injury. The good news is the 49ers don't consider it to be as severe as initially thought. Shanahan said his veteran offensive lineman is day-to-day.

Rookie Jaylon Moore replaced Williams.

"When he came in, he did a good job," Shanahan said of Moore. "He was thrust in there at the end too for the two-minute drill, which isn't always the easiest time to go in. But he did a good job while he was in, and if he needs to be ready this week, he'll have all week to prepare for it, and we'll give him even more reps than he's been getting, and we'll be ready to go with him."

Lastly, you have running back and special teams contributor Trenton Cannon, who has garnered criticism for his lost fumble on special teams, contributing to the Niners' second-half collapse.

Shanahan was asked if the team would consider a change at kick returner.

"I don't think so," he responded. "We'll look at it throughout this week. I think Trenton made a hell of a play versus Philly. He's looked good out there throughout his career when he has had those opportunities, and he's helped us this year, but that was a bad play that he made yesterday with the fumble, really bad. And I know it didn't help him the next play either.

"We have to evaluate that throughout the week, but I wouldn't say I have to make a change, but definitely have to have some competition there throughout the week."