BOSTON (CBS) —  Al Horford returns to Boston for the first time as a member of the Philadelphia 76ers on Thursday night. But he may not see the TD Garden floor.

Horford is listed as questionable to play Thursday night due to left knee soreness and left hamstring tightness, according to NBA reporter Keith Smith. The veteran forward played 31 minutes in Philadelphia’s win over the Denver Nuggets on Tuesday, scoring 11 points and pulling down nine rebounds.

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For the season, Horford is averaging 13.8 points, 6.8 rebounds and 3.9 assists per game for Philadelphia.

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Horford opted out of the final year of his contract with Boston over the offseason, and then signed a four-year, $109 million deal with their division rival. The Celtics and 76ers opened the season against each other, a 107-93 win for the Sixers in Philly, with Horford scoring 16 points against his former team.

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If he does play Thursday night, Horford will likely receive a pretty positive response from Celtics fans — at least at first. He was a fan favorite in his three years with the Celtics due to his team-first, do-everything attitude. That reception may change as the game goes on, especially if Horford helps the 76ers hand Boston their second straight loss.