"So, where does the Indianapolis Colts offense go after its discombobulated performance Sunday night?

Nowhere but up, fans will hope, and not just to Minnesota. But don't expect it to be easy.

A unit that almost certainly will be missing two starting linemen again -- guard Ryan Lilja, on the physically unable to perform list, and center Jeff Saturday -- now has another injury to worry about: Dallas Clark's right knee.

Team president Bill Polian said on his Monday evening radio show that team physicians were "fairly optimistic about Dallas and I have heard nothing . . . that tells me otherwise.

"I think we're in pretty good shape there.''

Clark suffered the injury in the second quarter of Sunday's loss to Chicago, returned briefly but didn't play in the second half. He had a magnetic resonance imaging test taken on his right knee early Monday -- the team did not announce the results -- and was at the light practice later in the day but did not participate.

"I'm hoping he'll be OK,'' coach Tony Dungy said. "He was running, trying to get himself back in the game (Sunday night).

"But if it is going to be a couple of weeks, we'll adjust.''

That could mean coordinator Tom Moore sticking with his two-tight end formation, which would mean relying heavily on rookies Jacob Tamme and Tom Santi, as well as Gijon Robinson, who played in his first NFL regular-season game Sunday.

Or it might mean more three-receiver sets, with Anthony Gonzalez starting along with Marvin Harrison and Reggie Wayne.

Any adjustment would come on top of the one forced by the knee injuries to Saturday and Lilja. Charlie Johnson and Dan Federkeil each made his first NFL start at guard against the Bears, while rookie Jamey Richard replaced Saturday at center.

"They did pretty well, actually,'' Dungy said of the interior linemen.

No one, however, was above criticism. That included Peyton Manning, who had a difficult time digesting the 29-13 loss. It was the quarterback's first appearance since offseason knee surgery and the Colts' first regular-season game in Lucas Oil Stadium, but there was little to celebrate.

"First game in a new stadium, 15th game in an old stadium, it is really disappointing to lose,'' Manning said. "So we have to go to work. Obviously there are some things we need to work on.

"Offensively we have to protect the ball better. You can't turn the ball over in this league and win.''

Mistakes included Marvin Harrison's fumble that Bears linebacker Lance Briggs returned 21 yards for a touchdown, and a safety when running back Joseph Addai was tackled in the end zone."