"Tight end Todd Heap likely won't be able to play in the Ravens' game against the Houston Texans Monday night.

Heap pulled his right hamstring running a seam route on the very first play of the team's eventual 13-10 loss to the Pittsburgh Steelers Sunday night. Heap did not return to the game, and coach John Harbaugh said Monday that it doesn't appear that Heap will be ready for Houston.

"I think Todd's probably the one that we really are concerned about," Harbaugh said. "I don't want to rule him out yet, but it doesn't look good for next week. It's one of those hamstring pulls that's going to be tough. The young guys are going to have to step up."

Rookies Ed Dickson and Dennis Pitta are the most likely candidates to fill in for Heap, who ranks second on the team in receiving touchdowns (5), third in receiving yards (546) and fourth in catch (37).

Dickson caught three passes for 22 yards, including two that gained first downs Sunday night. Pitta served as more of an H-back, blocking for tailbacks Ray Rice and Willis McGahee.

Dickson sounded as if he's ready for extended playing time in Heap's absence.

"So I just got in there and basically said, 'Do my job and not miss a beat,'" Dickson said after Sunday night's loss. "That's what we work on through the offseason [and] if something major happened like that, I'd go in and not miss a beat, and that's what we did."

Harbaugh, however, wasn't prepared to categorize Heap's injury as of the season-ending variety."