PITTSBURGH — Steelers receiver Limas Sweed may have dropped his way onto the bench.

Pittsburgh coach Mike Tomlin said Tuesday he may deactivate Sweed, the team's second-round pick last year, for Sunday night's game against the San Diego Chargers (2-1).

"Absolutely," Tomlin said at his weekly news conference when asked if he was considering benching Sweed in favor of veteran Shaun McDonald.

Sweed had one catch for 5 yards and dropped a pass in the end zone in the third quarter on Sunday as the defending Super Bowl champions fell to 1-2 with a 23-20 loss to the Cincinnati Bengals (2-1). Sweed, who missed the previous game with a foot injury, has a history of dropped passes in his young career — most famously a drop while wide open during last season's AFC Championship game.

"Quite frankly, he's not catching the football when he's deep down the field," Tomlin said. "He's got some tape that shows that. He's got to shake that off. If and when he's given his next opportunity to make a similar play, he better make it."

Tomlin said he was "concerned" about Sweed's inability to catch the ball when he's open. It is clear that rookie Mike Wallace, who is third on the team with 12 catches for 147 yards, has moved ahead of Sweed on the depth chart.

McDonald, a seven-year veteran, has 220 receptions for 2,490 yards and 11 touchdowns in 84 games with the St. Louis Rams and Detroit Lions, including 79 catches for 943 yards and six touchdowns with Detroit in 2007.

Another high draft pick from the Steelers' 2008 class who is not meeting expectations is running back Rashard Mendenhall. Mendenhall did not have a carry or a reception in Cincinnati after Tomlin said he had a poor week of practice, but Tomlin suggested he would be back as the No. 2 running back for this week's game.

"I don't have a doghouse," Tomlin said. "A doghouse is something you have when you let things stew and don't take action. He lacked a little detail in preparation last week ... Young guys have to earn their opportunities. They have to make coaches confident with their ability to execute details of their assignments. He didn't do that to my satisfaction last week and didn't get any playing time on offense as a result. I took action, but I don't take any baggage into this week."

Tomlin also said the Steelers would look into signing a fullback this week because of two injuries at the position. Rookie Frank Summers has a back injury and was examined by doctors on Tuesday, and rookie tight end/H-back David Johnson sustained a high ankle sprain. Tomlin said Johnson will be evaluated throughout the week but that he could be out several weeks.

The Steelers released Carey Davis late in the preseason. Davis was their starter at the position for much of 2007-08.

Tomlin said he "liked the progress" injured All-Pro safety Troy Polamalu was making in recovering from a torn medial collateral ligament in his left knee and said that starting running back Willie Parker has turf toe. Parker is expected to be fine this week but Polamalu is not expected back for at least another week.