"We're going to play him, since we have no choice," coach Doc Rivers said at Wednesday's shootaround at TD Garden. "We don't have enough players, honestly. You know we went into the game the other night with one [small forward] and two [shooting guards]. That's all we have. All of the middle position guys are out, from J.J. [Redick] to Matt Barnes and Reggie Bullock ... we don't have anybody."
The Clippers beat the Celtics 96-88. Jackson was largely ineffective, with no points on three attempts in 12 minutes off the bench.
Barnes (torn retina in left eye) and Bullock (left ankle sprain) are expected to miss the next two weeks. Redick is sidelined for at least another month with a broken bone in his right hand.
Jackson signed with the Clippers this week, joining a team for the first time since being waived by the San Antonio Spurs on April 27.
"We needed to get someone. I wanted a veteran. I know [San Antonio coach Gregg Popovich] well and I know what went on there, so we're hoping to give him another shot at it," Rivers said.
Rivers said he hopes the 13-year veteran will be a key contributor for the Clippers.
"In the long run, I want a post 3, which we don't have, and a guy who can make open shots and just some added toughness," Rivers said.
Jackson had played in 849 games over 13 seasons, with averages of 15.3 points, 3.9 rebounds, 3.1 assists and 1.3 steals in 32.1 minutes.
Brian Robb is a contributor to ESPNBoston.com.