Knight, 26, is 6-foot-10 and was waived by the Knicks late last week. He signed a two-way deal with New York over the summer. He spent the past two seasons with the Timberwolves, averaging 3.7 points each time.
Overall, he has appeared in 108 games over three seasons with the Wolves and Hawks, averaging 3.7 points and 2.0 rebounds.
Boston actually has four players on two-way contracts, so it will have to make a move. That is likely to come with the waiving of shooting guard Jay Scrubb, who suffered a torn ACL.