O'Neal started and played 11 minutes in the first half, contributing two points and three rebounds.
O'Neal said he had "no explosion" during the game and decided that the Celtics would be better off with him on the bench.
O'Neal missed time during the preseason with hamstring, back, and wrist injuries. The knee became sore after Boston's loss to Cleveland on the second night of the regular season, forcing him to sit out a game.
With Shaquille O'Neal (sore right knee) sidelined for five straight games, including Monday's tilt in Dallas, Jermaine O'Neal has made five straight starts.
Sunday in Oklahoma City, Jermaine O'Neal connected on just 1 of 5 shots for five points, but chipped in nine rebounds. This came after putting together his best offensive performance against Chicago on Friday (5-of-6 shooting, 12 points), but he didn't record a rebound in over nearly 20 minutes.
The Celtics opened the second half Monday with their core four starters alongside Glen Davis. They eventually lost 89-87.
Information from ESPNBoston.com's Chris Forsberg and The Associated Press contributed to this report.