The Steelers' injury situation at linebacker has gone from bad to worse.
Inside linebacker Stevenson Sylvester will be out three to four weeks after the medial collateral ligament in his knee was torn -- another blow to a unit that is already without Pro Bowl outside linebacker James Harrison and top backup Jason Worilds.
Sylvester, the top backup to inside linebacker Larry Foote, was injured on the final day of training camp at Saint Vincent College in Latrobe. He was replaced by former Cincinnati Bengals veteran Brandon Johnson, who moved from outside to inside linebacker in a 26-24 victory Sunday night against the Indianapolis Colts at Heinz Field
What's more, the Steelers are not certain when Harrison and Worilds will return.
Harrison has not practiced since early in the spring and had arthroscopic surgery on his ailing knee last week to expedite his recovery. Harrison has said he just wants to be ready for the season opener in Denver, but it appears he might not be ready to return until the second or third week of the regular season.
"We need 92 out there," Foote said of Harrison. "It's a different game when he's in there."
Worilds has missed all of training camp after having wrist surgery and it is still not known when he will be back. Worilds can't hinge his wrist to take on blockers and probably will have to wear some type of brace when he does return.
Chris Carter, a fifth-round draft choice from a year ago, has been the starter at right outside linebacker and played there again against the Colts.
"It's just another opportunity for someone to step up," Foote said. "The expectation doesn't change."
Former offensive coordinator Bruce Arians returned to Heinz Field with the Colts just eight months after he didn't have his contract renewed by the Steelers.
Arians said he was looking forward to his return and spent most of the pregame saying hello to his former coaching assistants and players.
"I'll get to see all my friends," Arians said.
Arians has inherited a young offense with the Colts, but he got a good head start in the draft. The Colts used the No. 1 overall pick to select quarterback Andrew Luck of Stanford and used their next two picks on the top tight end prospects in the draft -- Coby Fleener of Stanford and Dwayne Allen of Clemson.
Luck completed 16 of 25 passes for 175 yards and produced 17 points in the first half against the Steelers. But he was intercepted twice -- once for a 49-yard touchdown return by cornerback Ike Taylor.
"I've never seen anyone like him," said Arians, who has worked with quarterbacks Peyton Manning and Ben Roethlisberger in his career.
Rookie running back Chris Rainey returned to the game after it was announced he was being evaluated for a concussion.
Rainey took a hard hit from cornerback Jerraud Powers after an 8-yard gain on his first carry of the game. Rainey fumbled the ball and lay on the field after the hit.
But he returned to the game later in the quarter and even caught two short passes for 3 yards on the same series.
"They took me back inside, I took all the [concussion] tests, I passed and I was released," said Rainey, who carried six times for 20 yards. "I was normal so they let me back in."
The Steelers already are short on running backs. Isaac Redman (groin) did not dress and John Clay was waived injured last week after tearing his quadriceps muscle.
One game after he sprained his MCL in the preseason opener, rookie left tackle Mike Adams played with the second-team offensive line against the Colts.
Right tackle Marcus Gilbert moved to the left side and guard Ramon Foster started at right tackle against the Colts.
Even though he has been practicing at the "buck" linebacker position in training camp, Lawrence Timmons returned to his usual "mack" position against the Colts.
The buck position -- manned by Foote -- is responsible for calling the signals and setting the front seven in the defense. The Steelers want Timmons to learn the position in case something happens to Foote.
But the coaches are not ready to let Timmons play the position in a game.
Even though they all came off the physically unable to perform list last week, tackle Max Starks, nose tackle Casey Hampton and running back Rashard Mendenhall were among the players who did not dress.
Punter Jeremy Kapinos also did not dress after having back surgery two weeks ago.Steelers
Gerry Dulac: email@example.com; twitter: @gerrydulac. First Published August 20, 2012 4:00 AM