Celtics' Walker out until at least January after stem cell injection in knee

Toronto Raptors guard Kyle Lowry (7) tries to hold on to Boston Celtics guard Kemba Walker (8) during the second half of an NBA conference semifinal playoff basketball game Wednesday, Sept. 9, 2020, in Lake Buena Vista, Fla. (Mark J. Terrill/AP)

Boston Celtics point guard Kemba Walker has received a stem cell injection in his left knee and an update on his availability will be provided during the first week of January, the team announced Tuesday.

Following the procedure, the 30-year-old was placed on a 12-week strengthening program. He is expected to make his return to on-court activities in early December.

Stem cell injections are a form of therapy that aims to regenerate and repair damaged tissue. During the procedure, stem cells -- the body's raw materials, from which all other cells with specialized functions are made -- are taken from a person's bone marrow or fat and are injected into the damaged area, with the hope of triggering a healing response.

Walker's left knee has been problematic for several years. In 2016, he underwent surgery to repair a torn meniscus and throughout the 2020 season he experienced intermittent bouts of soreness that caused him to miss games, culminating in him being on a minutes restrictions throughout the Celtics' post-season run in the Orlando bubble.

In 56 regular-season games for Boston last year, Walker averaged 20.4 points and 4.8 assists. He struggled at times during the Celtics' run to the Eastern Conference Finals, but managed to average 19.7 points per game in the Eastern Conference Finals against the Miami Heat.

The Celtics also announced that new off-season acquisition Tristan Thompson suffered a minor hamstring strain during a workout prior to arriving in Boston, and his availability during the first week of the team's training camp will be limited.

Boston's first pre-season matchup is Dec. 16 against the Philadelphia 76ers, with the NBA season slated to begin officially on Dec. 22.

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