Los Angeles Rams quarterback Matthew Stafford was replaced by Brett Rypien at the end of the third quarter in L.A.'s 43-20 loss to the Dallas Cowboys on Sunday afternoon while dealing with a thumb injury.

Stafford injured his thumb in the first half of the matchup at AT&T Stadium after it collided with the helmet of Cowboys defensive tackle Mazi Smith. His thumb started bleeding significantly, and Stafford went to the locker room to get it checked out.

Stafford returned to the game to start the third quarter where he led the Rams on a 75-yard touchdown drive and caught a two-point conversion on a pass from Tutu Atwell to briefly cut Dallas’ lead to 17 points.

Yet right before the third quarter ended, Stafford went back to the locker room and re-emerged with his right hand heavily taped. The Rams then went with Rypien, who had yet to play this season.

The Rams (3-5) officially listed Stafford as questionable to return after Cowboys quarterback Dak Prescott hit Brandin Cooks for a 25-yard touchdown early in the fourth quarter. That gave Dallas a 43-17 lead at the time. Stafford remained out for the rest of the way as Dallas cruised to the 23-point win.

Stafford went 13-of-22 for 162 yards with a touchdown and an interception before he went down. He entered the day with 1,908 yards and seven touchdowns with six interceptions this season.

Rypien went 5-of-10 for 42 yards to close out the blowout loss. Royce Freeman led the Rams on the ground with 44 yards and a touchdown on nine carries, and Darrell Henderson Jr. had three catches for 54 yards.

The Rams have lost three of their past four games.

Prescott, on the other hand, went 25-of-31 for 304 yards with four touchdowns and an interception in the win, which brought Dallas to 5-2 on the season. Tony Pollard had 53 rushing yards on 12 carries, and CeeDee Lamb had 158 yards and two touchdowns on 12 catches.