Quarterback Brock Purdy and star running back Christian McCaffrey will not play as the top-seeded 49ers prepare for the playoffs. Former USC star Sam Darnold will start in place of Purdy. Darnold, the No. 3 pick in the 2018 draft by the New York Jets, has completed 12 of 20 passes for 108 yards and a touchdown, with an interception, this season. Coach Kyle Shanahan might hold out other star players such as Deebo Samuel, who has scored 12 touchdowns, receiver Brandon Aiyuk and tight end George Kittle. Last Sunday in a 27-10 victory over the Washington Commanders, running back Elijah Mitchell rushed for 80 yards and a touchdown in 17 carries. Rams coach Sean McVay will hold out 10-time Pro Bowl lineman Aaron Donald and linebacker Ernest Jones as part of his plan to rest starters for the playoffs. Rookie tackle Kobie Turner has tied Donald’s Rams rookie record with nine sacks. Rookie edge rusher Byron Young has seven sacks. Safety Jordan Fuller has intercepted passes in each of the last two games. Fuller could be among starters pulled from the game if the outcome is decided early but the Rams have been prone to giving up explosive plays, especially late in games when they should have had the outcome in hand.