KANSAS CITY, Mo. — Brodie Croyle limped over to the sideline, slammed his helmet to the turf, then hobbled down the tunnel behind Kansas City's bench.

Just 14 plays into his return from a separated shoulder, Croyle suffered yet another injury, this time a sprained right knee that sent him off the field in the second quarter against the Tennessee Titans on Sunday.

The oft-injured Chiefs quarterback is likely done for the season with ligament damage and may have lost his already-tenuous hold on the job for good.

"He's been hurt, there's no doubt about that," Chiefs coach Herm Edwards said. "This is the worst one he's had. This is a tough one here. This is the rest of the year, so it's tough on everybody; tough for him, tough for this football team."

Croyle missed the previous four games after injuring his throwing shoulder against the New England Patriots in the season opener. The Chiefs had hoped the third-year player from Alabama could provide a lift to an offense that had just 127 total yards in its previous game, a 34-0 loss to Carolina on Oct. 5.

Instead, Croyle's disappointing history of injuries added a new chapter when two onrushing Titans defenders hit him on a pass attempt early in the second quarter, twisting his knee. He completed the 17-yard pass to Dwayne Bowe, but had trouble getting up and couldn't put any weight on his right leg as his hopped toward the sideline.

Croyle disappeared into the tunnel and didn't return, replaced by Damon Huard after completing 9 of 10 passes for 63 yards. It was the fourth time in eight starts Croyle had suffered an injury.

"My heart goes out to him," Chiefs tight end Tony Gonzalez said. "He's worked so hard. He's been so tough with his injuries. It's just not fair."

Croyle was injured in his first career start at Arrowhead Stadium, taking a knee to the lower back against Oakland last November. Croyle finished that game, but was out the following week against San Diego. He was injured again a month later, missing the second half against Detroit after injuring his hand while making a tackle on an interception.

Croyle also had his share of injuries at Alabama despite setting numerous school records, separating his shoulder and cracking ribs as a sophomore, missing most of his junior season with a torn ACL. This after tearing the ACL in the other knee in the first game of his senior season at Westbrook Christian High School (Ala).

The Chiefs used a third-round draft pick on Croyle in 2006, declaring him their quarterback of the future. His latest injury may have put an end to that.

"I feel bad for the kid, I really do," Edwards said. "He did everything in his power to try to come back. He had a good week of preparation, he was excited about coming back, now his season's over."

Croyle's injury leaves the Chiefs in a tough spot.

Huard spent most of the fourth quarter with his right thumb heavily taped and his status for next week's game against the Jets is still in the air.

Tyler Thigpen put together two scoring drives in the fourth quarter to help the Chiefs avoid the shutout, but has seemed overmatched at times in place of Croyle and Huard. He'll get the start if Huard can't play next week, though Kansas City will likely have to bring in someone else as his backup since Ingle Martin isn't ready to play in the NFL.

"I think he's still too raw, so we'll have to make some decisions," Edwards said. "We'll have to huddle up here and make some decisions about what direction we need to go with the quarterback situation."