X-rays on the shoulder were negative, but the Mavs announced early in the third quarter that Marion would not return.
Marion fell hard to the floor after tripping over the Lakers' Pau Gasol and teammate Dirk Nowitzki late in the second quarter. Marion, who had eight points and seven rebounds in 15 minutes against the Lakers, stayed down for several minutes and headed straight to the locker room with an athletic trainer after getting up.
Marion, Dallas' best defensive player, entered the game averaging 11.4 points and 7.2 rebounds. Wayne Ellington replaced him in the starting lineup for the second half.
Marion was playing with a sprained right ankle suffered in Sunday night's loss to the New York Knicks.