SANTA CLARA, Calif. (AP) -- Carlos Rogers understands a key piece of San Francisco's defense is missing with the absence of Aldon Smith, yet the veteran cornerback is determined to make sure it never becomes an excuse for the team's recent poor play.
The 49ers are moving forward without their star linebacker and sacks leader as he begins rehab for substance abuse and an indefinite leave from the team. He played in Sunday's 27-7 loss to the Colts, but is gone now following his second DUI arrest in 20 months last Friday morning that also included suspicion of marijuana possession.
Smith apologized Sunday night. Defensive coordinator Vic Fangio has no idea how long Smith might be away, and that seems to be the case all around.
''I think it's a distraction to whoever wants to think about it, to whoever wants to pay attention to it,'' Rogers said Tuesday. ''When I get out there on the field and play, I'm thinking about playing whatever team, I'm not thinking about Aldon and whatever situation went on with him. We're going to continue our meetings, we're going to continue to go on the field and practice, whether he's here or not. That's the only thing we can do. For each individual, if you continue to worry about Aldon and let that be a distraction, let that say, 'Oh, this team's not going to be the same because Aldon's not here,' then it will be a distraction.''
While everybody in the locker room is rooting for Smith's recovery, his fellow defenders are now focused on getting the most from the guys who will take over for him: Dan Skuta and Corey Lemonier, among others.
''We believe he'll be healthier, and not just as a football player but as a normal human being, and we wish him the best of luck,'' safety Donte Whitner said. ''But we believe that the guys who are going to back him up - Skuta and Lemonier - they're going to go in there and they're going to do a great job. Everybody else has to pick up their play with Aldon not being out there.''
A defense that has been so dominant stopping the run in recent years suddenly ranks a surprisingly low 29th in the league, with opposing offenses running against the NFC champion Niners (1-2) at every chance.
''We've let a couple of them pop, which we haven't done in the past which skews the statistics,'' Fangio said. ''And we've been in games where they've been able to hand it off a high amount of times. So, I think it's a combination that we haven't been as sharp and the type of games we've been in.''
Expect the St. Louis Rams to do more of the same Thursday night without Smith, and perhaps also fellow All-Pro Patrick Willis as he nurses a groin injury. And the 49ers will miss the menacing, swarming presence of Smith, who set a franchise record with 19 1/2 sacks last season in helping San Francisco reach the Super Bowl.
Skuta, signed to a two-year contact after he had 26 tackles last season and a team-leading 17 tackles on special teams for the Bengals, is ready to help fill a huge void - knowing how well Aldon Smith and Justin Smith complement each other on an imposing front seven.
''I've always paid attention to how they played together,'' Skuta said. ''They did a great job in there together with communication and all their different stunts. If we get that opportunity, I'd like to do that stuff, too. I think I would fit in and do the same type of thing.''
While San Francisco's defense committed five penalties leading to first downs for Indianapolis, Whitner said he heard from the NFL on Monday that his hit on Ahmad Bradshaw on the Colts' first snap shouldn't have been a 15-yard unnecessary roughness penalty for a helmet-to-helmet tackle and he won't be fined.
Whitner thought he clobbered Bradshaw in the shoulder area, and said the league agreed.
''They called and our coaching staff talked to the league and they said it wasn't a penalty and I wouldn't be fined,'' Whitner said. ''Especially after seeing what (former teammate) Dashon (Goldson) is going through, I was relieved.''
For now, Rogers remains confident the 49ers will bounce back Thursday night and regain the defensive swagger that has carried this team so far the past two seasons.
''Our team, GM, the coaches, the owners, they put a good team together, put up good starters, put up good backups,'' Rogers said. ''So that next person's got to come in and play to the level of him or better than him. It's hard to say that being how good Aldon is, one of the best defensive players in the league, but we've got to pick up the slack and rally around the person who's his backup. Even with Pat, if he's out, everybody's got to pick up their slack and just continue to work and get better and not let it be an excuse. If it does, we're going to continue to fall and continue to lose games.''
With Smith's departure opening up a spot, the 49ers on Tuesday promoted cornerback Darryl Morris to the 53-man roster and signed linebacker D'Aundre Reed to the practice squad.
Cornerback Nnamdi Asomugha could be sidelined with a leg injury, so adding Morris provides depth in the secondary. On the offensive side, coordinator Greg Roman said the status of both tight end Vernon Davis (hamstring) and running back LaMichael James (knee) will likely be game-time decisions.
AP NFL website: www.pro32.ap.org