The Browns dropped their fourth straight home game on Sunday and will likely be without quarterback Derek Anderson for their final four games.
Anderson, starting in place of the injured Brady Quinn, sprained the medial collateral ligament in his left knee when he was hit by the helmet of his teammate in the closing minutes. Beleaguered Browns coach Romeo Crennel said Anderson "may be in tough shape" and said Ken Dorsey is his starter for next Sunday at Tennessee.
On Cleveland's last drive, Anderson, making his first start since being benched by Crennel, was dropping back to pass when offensive tackle Kevin Shaffer was knocked back into him by a charging Robert Mathis. Anderson tried to get up, but couldn't and had to be helped to the sideline. Dorsey came in for the final three plays and was intercepted on the Browns' last snap.
"It's not very good," said Anderson, who will undergo more tests on Monday. "I felt a burn, a pain. It's disappointing."
The Browns also lost tight end Kellen Winslow, who went out on the first play of the third quarter with an ankle injury and didn't return.
The Buffalo Bills also lost their starting quarterback in a tough loss at home.
The pain in Trent Edwards' sore groin grew worse with each step he took, forcing him to the sideline midway through a 10-3 loss to San Francisco that all but dashed what's left of Buffalo's playoff hopes.
And it's unclear whether Edwards will be healthy in time to play next weekend when Buffalo hosts Miami at Toronto.
"As of right now, I have no idea," Edwards said. "We're going to have to re-evaluate it again tomorrow."
Edwards characterized the injury as either a pull or a strain.
"It is unfortunate. It's frustrating," he said. "And I need to get in the training room and get better."
Edwards went 10-of-21 for 112 yards before being replaced by J.P. Losman for the start of the second half.
Edwards said his groin began bothering him at the start of the game and that the pain became more severe every time he was knocked down. The worst came after the final play of the second quarter, when Edwards rolled to his right and completed a 24-yard pass to Josh Reed along the right sideline as time ran out.
"It really kind of put it over the top," Edwards said. "We made the call to just shut it down."
Edwards spent the second half watching from the sideline wearing a black rain coat and with a wool cap pulled over his head.
The Patriots did not announce the nature or severity of his injury.
With Pittsburgh leading 23-10 during its 33-10 win, Matt Cassel's pass to Welker went incomplete and the receiver was knocked down by Clark, who was penalized 15 yards for unnecessary roughness. New England ended up losing a fumble on that series.
Welker finished with four catches for 30 yards, ending his NFL record streak of 11 games with at least six receptions to start a season. He entered the game with 80 receptions, second in the NFL to Houston's Andre Johnson, who had 81.