"There's no excuses to be made," Stewart said. "I don't want pity or no one to feel sorry for me."
Stewart's passer rating Sunday was 2l.9, or about 7 points worse than Burris' rating for last season.
Stewart took several vicious hits and was the victim of an inexperienced line. After Chris Villarrial left in the second quarter with a knee sprain, the Bears' offensive line had one player starting who started on opening day last year -- Olin Kreutz.
"I'm not going to point my finger at one thing, but when you turn the ball over like we did and they capitalize, the outcome will be like this all the time," said Stewart, who lost a fumble and threw three interceptions.
Stewart stuck up for his linemen, but said there isn't time at this point to dwell on their problems.
"We have grown men on the offensive line and we have a system to run," Stewart said. "We don't have time now (to panic). We don't have time to worry about inexperience."
Stewart holds the ball longer than Jim Miller did last year when he runs the offense. Shoop said he'll have to study this week how much the team's failure to pass protect had to do with that potential problem.
"San Francisco did a good job, obviously, of pressuring him," Shoop said. "We didn't protect him well enough and we were unable to really get into a rhythm.
"I have to look at the film and those are questions I have to ask him as well."
Bears coach Dick Jauron wouldn't point any blame at Stewart, either.
"There wasn't a whole lot that went right," he said when asked specifically about Stewart, who matched a career high with his three interceptions. "I couldn't talk about it in detail because I haven't seen the tape. We practiced well and the game was horrible, but we'll examine it."
If there is a problem with the pass rush, Stewart said it's his responsibility to find a way to deal with it.
"This game of football is all about pressure, and the thing is being able to react to it," Stewart said.