Trent Williams will play on Sunday

Some key 49ers players won't play in a meaningless Week 18 game against the Rams. Veteran left tackle Trent Williams will.

Coach Kyle Shanahan told reporters on Friday that Williams is indeed playing.

“I don’t think it’s good for anybody to take two weeks off,” Shanahan said earlier in the week. “You should see how Trent was when he came back after a month off or three weeks. It’s not good, but we’ll see how the game goes and everything. His mindset this week’s got to be that he is getting ready to play.”

It's possible Williams won't play much. The goal is to keep the players in a routine, especially for the teams that earn a bye week.

To go three weeks between playing can lead to being not as ready as the player needs to be when it's time to hold serve in the divisional round. The teams that earn the lone bye per conference are always playing a team that played and won in the wild-card round — and that enters the divisional-round with a nothing-to-lose mentality.

That can become a real problem for a team that potentially will see its special season evaporate in three hours against a team that caught it flat-footed.

Still, it's a calculated risk for the 49ers. If Williams gets injured in a meaningless game and can't play in the divisional round, that will make it harder to win when the 49ers host a wild-card winner in 15 or 16 days.