NASHVILLE, Tenn. — While defending their quarterback from critics worried about his mental state today, the Tennessee Titans had to reschedule a test on Vince Young's sprained left knee.

Detractors claimed Young quit on his team in the season opener.

Young was intercepted midway through the fourth quarter of the 17-10 win over Jacksonville and walked to the sideline to a heavy chorus of boos from the hometown fans. He threw his helmet and sat on a bench with a towel over his head. His defense forced Jacksonville into a three-and-out, and the offense went on the field — with Young still on the sideline.

Backup Kerry Collins started taking a couple practice snaps, and coach Jeff Fisher pulled off his headset to talk with Young. The quarterback then put on his helmet and took the field. Four plays later, he rolled out on a bootleg and Jaguars linebacker Daryl Smith collided with Young's left knee.

Fisher said at his Monday afternoon news conference that they did not have the test results on Young's knee. The team said approximately four hours later that an MRI had to be rescheduled for Tuesday. The team promises to release the results then.

Fisher still faced questions about what happened Sunday. As he did then, Fisher said the discussion only involved Young's tight hamstring and whether he could play.

Asked about how upset he looked, Fisher cautioned against reading too much into his taking off the headset.

"I had an offensive group on the field and the referee is getting ready to wind the play clock, and I had a quarterback on the sideline. If I appeared upset, it's because I wanted to get my quarterback on the field so we could go. So that's the long of it. I think we're making an awful lot over the fact that there was some communication on the sideline," Fisher said Monday.

"I think the bigger issue now is his knee. I'd be (more) concerned about his knee than what happened yesterday."

"Obviously, if you're dealing with a third-degree MCL sprain, you're probably out a couple of weeks and not back to 100 percent for three or four weeks," Fisher said.

If Young can't play Sunday at Cincinnati, Collins is the only other quarterback on the roster. Ingle Martin is on the practice squad, and Fisher said no one had been contacted about visiting the team. He also said he had no knowledge of a report that Chris Simms was coming for a visit.

Fisher said promoting Martin, a sixth-round pick by Green Bay in 2006, made the most sense because he knows the offense.

But Young's commitment to his team was the hot topic around Nashville, even after the Titans found themselves atop the AFC South after just one game. This is the quarterback who told a reporter this offseason he had thought about retiring after winning Offensive Rookie of the Year in 2006. Young said that was taken out of context.

Young struggled even as the Titans went 10-6 and reached the playoffs almost in spite of him last season. He had nine touchdowns with 17 interceptions in 2007. Fisher brought in a new offensive coordinator, but the quarterback went through the preseason without leading the first-team offense to a touchdown.

Fisher said there's no doubt the emotional Young needs to work through "some things" with his sideline demeanor.

"It's not the first time he's been frustrated or he's shown frustration outwardly on the sideline," Fisher said. "But he tends to bounce back. He was not happy after the first interception, and he clearly should not have thrown that ball. He made that decision, he understood it, he processed it. He came back two series later and led us on a touchdown drive."

Veteran center Kevin Mawae defended Young, saying that dealing with bad things in a game is a learning process. He recalled apologizing to Warren Moon for being unable to block Junior Seau himself once. Being booed by the hometown crowd is even more frustrating, but must be blocked out.

"As long as the guys that are next to you believe in you, I think that's the most important thing. I think Vince knows that he has the backing of every guy on this team. ... But at some point it's got to come down to that single individual person to know that he's got a job to do just like everybody else," Mawae said.