Marion strained a left oblique muscle in the first half of Saturday's game and did not practice the last two days, instead being limited to cardio work Tuesday. Carlisle said Marion's status beyond Wednesday is day to day.
"If we have to fill in for him, we will," Carlisle said.
The 6-foot-7 Marion has typically guarded the opponent's top scorer. When he couldn't play in the second half against Oklahoma City, Butler took over defensive duties on Kevin Durant.
Without Marion's lanky frame and long arms to guard the wing position, the Mavs will have to adjust at a critical juncture in the season. Headed into Tuesday's games, they are locked in a four-way tie for the second playoff seed with five games remaining.
With what can be a tricky abdominal injury, the Mavs could possibly be without Marion for some or all of their upcoming three-game road trip over four days that starts Friday night at Portland.
"We've just got to do it all together. Defense is five players together, not one-on-one, and that's how we have to look at it," Dirk Nowitzki said. "Help each other, scramble for each other, cover for each other. If you give up anything, it's got to be contested jump shots and not layups."
Marion, who is averaging 11.9 points and 6.4 rebounds, has dealt with calf, ankle, groin and back injuries this season but has missed only four games.