The Boston Celtics worked out former first-round pick Thomas Robinson on Monday, sources told ESPN's Adrian Wojnarowski.

The workout is notable because the Celtics have an open spot on their 15-man roster, so long as the blockbuster Kyrie Irving-for-Isaiah Thomas swap with the Cleveland Cavaliers does not fall apart. Sources previously told Wojnarowski that the Cavaliers could seek additional assets given the hip injury that might sideline Thomas at the start of the 2017-18 season.

Boston could simply be performing due diligence while examining an available free agent but the workout might also hint he team believes the Irving deal will ultimately remain intact.

With rookie 7-footer Ante Zizic shipped to Cleveland as part of the package for Irving, the Celtics' most glaring need is for rebounding. In 48 games for the Lakers last season, Robinson, the No. 5 pick in the 2012 draft, posted a total rebound rate of 22.5 percent, including grabbing 30.4 percent of all available defensive rebounds while on the court. For comparison, since-departed Kelly Olynyk led Boston last season with a total rebound rate of 13.1 percent while grabbing a team-best 20.7 percent of defensive caroms.

In an interview with HoopsHype at the start of free agency in July, Robinson said, "Given the opportunity, I could easily be among the top 10 rebounders in the league. Easily."

The 26-year-old Robinson has played for six teams in five NBA seasons. For his career, the 6-foot-10 big man has averaged 4.9 points and 4.8 rebounds over 13.4 minutes per game. In the final month of the 2016-17 season, Robinson averaged 9.3 points and 6.7 rebounds in 17.9 minutes per game for the Lakers, who won five of their final seven games.

Sources also told Wojnarowski that the Celtics have signed undrafted Georgetown swingman L.J. Peak to a partially guaranteed deal to join them for training camp. Peak is a candidate to be funneled to the team's G-League affiliate in Maine.