SANTA CLARA – Alex Smith practiced for the second straight day Thursday and remains on track to start for the 49ers on Monday against Chicago.

Bears coach Lovie Smith, however, said his team was preparing to face backup quarterback Colin Kaepernick, too.

"Colin has been playing some anyway, so we've been preparing for that anyway," Smith said. "Again, we don't change what we do an awful lot based on change in the quarterback. Both of those quarterbacks have played some for them."

Alex Smith was dressed in a black, no-contact jersey for the second day in a row and was listed as a "limited" participant in Thursday's practice. On Wednesday, Smith said he felt good, and his practice routine over the past two days has looked normal, at least in the early portion of the sessions that has been open to the media.

The last step in returning from a concussion is to be cleared for contact practice, which Smith said was odd considering quarterbacks don't receive any contact in practice even when healthy.

"Had the black jersey on me, which is a little redundant, seeing as how we don't get hit in practice," Smith said Wednesday. He was not available to speak to reporters Thursday.

Tweet nothings – Running back Brandon Jacobs, who has a history of making controversial remarks, said he was not referring to his relationship with the 49ers in a tweet he posted Thursday.

The tweet – "Never work in a place where you hate your boss so much, you should be happy at work #YouLiveAndYouLearn" – was delivered just minutes after news broke that Jacobs' boss, Jim Harbaugh, was in the hospital being treated for an irregular heartbeat.

Asked about the tweet in the locker room, Jacobs angrily replied: "People automatically assume it has something to do with this (expletive) sport. It's not. I have different companies and different businesses. I have a life outside of football."

Jacobs later tweeted that the original tweet was about his brother, who had been laid off recently.

Despite recovering from a knee injury more than a month ago, Jacobs hasn't played a snap for the 49ers. Before the 49ers played his former team, the Giants, on Oct. 14, he said he was frustrated by the situation. But he has told reporters he is being patient.

Injuries – Cornerback Chris Culliver (shoulder) was listed as limited.

Nine injured 49ers practiced Thursday, including starters Dashon Goldson (ribs), Jonathan Goodwin (ankle), Frank Gore (ribs, wrist), Mike Iupati (quadriceps), Mario Manningham (shoulder) and LB Patrick Willis (shoulder).

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