Cleveland Cavaliers center Tristan Thompson is expected to miss one month with a left calf injury, league sources told The Vertical.

Thompson suffered the calf strain in Wednesday’s home loss to the Indiana Pacers, which dropped Cleveland to 3-5 on the season. Thompson accepted a reserve role this year but had returned to the starting lineup, averaging 4.4 points and 6.1 rebounds in eight games (five starts). He has averaged 9.3 points and 8.6 rebounds for his career.

Thompson has been an iron man for the Cavaliers in seven seasons, and his extended absence means the team will be without its top interior defender.

Thompson, 26, was drafted fourth overall out of Texas by Cleveland in 2011. He started all 21 postseason games for the Cavs in their championship season of 2015-16.