Dixon is to have a torn lateral meniscus in his left knee repaired. He will miss up to five weeks during rehabilitation.
The Steelers re-signed Byron Leftwich Monday, two days after releasing him. Leftwich suffered a sprained knee ligament in the team's final pre-season game. It is unclear is he is healthy enough to challenge Batch for a starting position.
"You've got say that Charlie has the pole position, if you will, because he's got a clean bill of health at this point," Pittsburgh Coach Mike Tomlin said. "We don't anticipate Byron's health being an issue but at this point, at least, you have to acknowledge that could be a factor."
Leftwich was expected to handle the quarterbacking duties for the first four games of the season while regular starter Ben Roethlisberger served a four-game NFL suspension.
But the Leftwich injury led Tomlin to turn to Dixon, who helped the Steelers' to a season-opening win. He was hurt in the first quarter of last Sunday's game, which also was won by Pittsburgh.
Batch has been in the NFL since 1998 but has started just four games since 2001.