SAN FRANCISCO (AP) -- Dozens of players reverently crowded around the cart to offer words of encouragement to Koy Detmer. The game was all but decided, and Detmer's fine play earned admirers in both uniforms.

As long as the Philadelphia Eagles don't run out of quarterbacks before the end of January -- a distinct possibility at this rate -- there might be no limit to how far their impressive offense can go.

Filling in tremendously for injured Donovan McNabb, Detmer passed for 227 yards and two touchdowns and rushed for another score before leaving with a dislocated left elbow late in the Eagles' 38-17 win over San Francisco on Monday night.

Detmer's big night began and ended with a fall. He tripped on the first play from scrimmage, and he hurt his elbow late in the third quarter, his legs flailing in excruciating pain after his awkward landing. Before he was carted off, the Eagles' entire bench emptied onto the field to wish him well along with the Niners' defense.

"It meant a lot to me," Detmer said. "I was in pain and disappointed at the same time. It was an incredible night up to that point. ... That was a great show of sportsmanship on (San Francisco's) part. They showed me a lot of respect."

Nobody will know how long Detmer will be out until he's re-examined in Philadelphia on Tuesday, but third-stringer A.J. Feeley, who finished for Detmer, expects to start Sunday against St. Louis.

Before the fall, Detmer completed 18 of 26 passes while executing with remarkable precision for a player who'd thrown just 17 passes since 1999. McNabb is expected to miss the rest of the regular season with a broken ankle, but in Detmer's first start since 1999, he was outstanding for nearly three quarters.

"Koy's a pretty tough nut, so if he's rolling around out there, you know there's something wrong," coach Andy Reid said. "It wasn't a cheap shot or anything."

Using all of his many options in Reid's unpredictable game plan, Detmer carved up the 49ers' confused secondary and staked the Eagles (8-3) to a big lead. In particular, Reid picked on rookie Niners defensive back Mike Rumph incessantly.

Detmer, his arm still pulsating with pain after team doctors shoved his elbow back in its socket, stood on the sideline with a grin on his unshaven face, watching his teammates finish off the Niners in a one-sided meeting of division leaders.

Feeley hadn't thrown a pass all season, but hit Chad Lewis for a 1-yard TD moments after Detmer left -- and the Eagles were all but assured of a conference victory that might turn out to be pivotal when playoff seedings are determined in five weeks.

"It always helps when you get some extra work," Feeley said. "Whoever's out there, we have confidence in the game plan."

Brian Mitchell returned a punt 76 yards for a touchdown.

Terrell Owens had 13 catches for 166 yards and two TDs, but in spite of a warm night on Candlestick Point and the Eagles' desperate quarterback situation, the 49ers were terrible on both sides of the ball while losing at home for just the third time in two seasons.