SANTA CLARA -- For the first time in his 42-game NFL career, 49ers running back Matt Breida suited up but did not touch the ball.

Breida did not play a snap of offense in the 49ers’ 34-31 victory Saturday over the Los Angeles Rams. But that was not by design, 49ers coach Kyle Shanahan said this week.

“We didn’t go in not planning for him to not have any plays on offense. It just worked out that way,” Shanahan said of Breida.

Tevin Coleman started for the 10th time this season, but Raheem Mostert quickly entered the game and ended up getting more playing time. The 49ers had 57 offensive snaps against the Rams. Mostert played 31 snaps, while Coleman was on the field for 24 offensive plays.

Shanahan said the circumstances of the game did not set up well for Breida to get involved in the offense.

“Went through a little bit of a lull in the third quarter where we had a number of three-and-outs, so it was tough to sub him in,” Shanahan said. “We didn’t have any long drives. The runs that the other two guys did get, they were being effective. It was nothing against Matt. Just unfortunate how the game worked out for him.”

Breida started five of the 49ers’ first seven games after Coleman missed time early with an ankle sprain. At that point, Mostert had yet to establish himself as a reliable runner. Breida sat out three games with an ankle injury but came back to carry six times for 54 yards on Dec. 8 against the New Orleans Saints.

But in the 49ers’ Week 15 loss to the Atlanta Falcons, Breida had four carries for 11 yards. He also fumbled twice and lost one of them for a crucial second-half turnover. In the 49ers' following game, Breida did not see action on offense, but played nine snaps on special teams.

Shanahan was asked if Breida’s fumbles factored into the team’s decision to keep him on the sideline against the Rams.

“No, it wasn’t,” Shanahan said. “We just planned on Tevin starting. Like the week before, we planned on going to Raheem pretty fast. It just never came up that way.”

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Mostert is the 49ers’ leading ground-gainer with 715 yards and six touchdowns on 127 rushing attempts (5.6-yard average). He also has 13 receptions for 164 yards and two touchdowns.

Breida has gained 607 yards and one touchdown on 119 attempts for a 5.1 average. Breida has 19 catches for 120 yards and a touchdown.

Coleman has 533 yards and six touchdowns on 132 attempts for a 4.0 average. Coleman has also caught 20 passes for 173 yards and one touchdown.

The 49ers’ fourth running back, Jeff Wilson, has carried 27 times for 105 yards and four touchdowns. Wilson, who has appeared in 10 games, has three catches for 34 yards, including a game-winning 25-yard touchdown reception from Jimmy Garoppolo against the Arizona Cardinals on Nov. 17.