The San Francisco 49ers are facing the Seattle Seahawks in a crucial Monday night matchup, but they at least temporarily lost one of their top offensive players, as wide receiver Emmanuel Sanders was forced out of the game early with a rib injury.

Acquired via trade in late October, the two-time Pro Bowler hit the locker room just more than 10 minutes before halftime, clutching his side during an incomplete pass from Jimmy Garoppolo. Sanders had logged two catches for 24 yards against Seattle before sustaining the injury, which also appeared to occur before the former Denver Broncos standout was contacted by Seahawks defensive back Jamar Taylor.

The Niners initially ruled Sanders questionable to return to Monday's contest but downgraded the veteran to out early in the second half.

Since joining San Francisco, the 32-year-old wideout has been arguably the most reliable pass target in Kyle Shanahan's offense. Acquired along with a future fifth-round draft pick in exchange for third- and fourth-round picks, he caught four of five targets, including a touchdown, in his Niners debut, then went off for seven catches, 112 yards and a score during San Fran's 28-25 victory over the Arizona Cardinals in Week 9.

Rookie Deebo Samuel figures to see a continued uptick in snaps during Sanders' absence.

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