CLEVELAND (AP) — The defending NBA champions will be without a major piece for at least three months.

Cavaliers starting guard J.R. Smith could be sidelined until the end of the regular season following surgery to repair what the team called a “complex fracture” of his right thumb. Smith’s injury will have a major ripple effect on the Cavs, who have dealt with numerous injuries over the past two seasons.

Smith hurt his thumb late in the first half on Tuesday night at Milwaukee when he swiped at the ball. The 13-year veteran, who signed a four-year, $57 million contract in October, attended Wednesday’s game and sat on the bench in street clothes with his thumb immobilized in a large soft wrap, a sign that the injury was more significant than originally believed.

The Cavs said the surgery was completed Friday by renowned hand surgeon Dr. Thomas Graham, who was assisted by Dr. TJ Reilly and team physician Richard D. Parker at the Crystal Clinic Orthopaedic Center in Montrose, Ohio.

Smith will need 12 to 14 weeks of recovery time, which means he may not be back until early April. The Cavs play their final game of the regular season on April 12 and begin defense of their title three days later in the playoffs.

Although Smith was averaging just 8.6 points on 34 percent shooting, he’s one of the team’s best perimeter threats and wing defenders. His loss will force coach Tyronn Lue to make adjustments with his rotations and general manager David Griffin to alter the team’s roster.

The Cavs have been looking for a backup point guard since training camp, but Smith’s injury could change their priorities. Lue said he told Griffin to “take his time” in his search for a point guard, but that was before the severity of Smith’s injury was known.

DeAndre Liggins started in Smith’s spot on Wednesday in a win over Milwaukee. It’s possible veteran Mike Dunleavy and Jordan McCrae could get more playing time while Smith is out.

Also, Smith’s absence could have an effect on when Lue gives superstar LeBron James some rest. The Cavs are expected to taper James’ minutes in January so he is as fresh as possible for the postseason.

One positive is that the Cavs have been forced to adjust because of injures before and that experience will help while Smith recovers.

James expects everyone to step up.

“It’s tough when you lose guys that mean so much to the success of our team,” James said following Wednesday’s win, Cleveland’s eighth in nine games. “Obviously it’s going to be a while until we get J.R. back, so it’s next man up. And guys have to fill in, guys have to fill in and play their role. Don’t play J.R.’s role. J.R. is a special talent so you don’t try to play his role, you just try to do more on your own and try to help the team win, so hopefully we can get that.”