To make room, the Knicks parted ways with forward Corey Brewer, a day after waiving guard Kelenna Azubuike.
The 6-foot-11 Jeffries originally signed with the Knicks on Aug. 8, 2006, and played for the team until he was traded to the Houston Rockets last season at the trade deadline.
The Knicks value Jeffries for his ability to defend anyone from big men to point guards, and moved quickly to sign him once he cleared waivers after being bought out by the Rockets last week. He is expected to be in uniform when New York hosts New Orleans on Wednesday.
Brown was waived by Charlotte last Thursday. The 6-8 forward averaged 3.4 points in 10.4 minutes per game over two seasons with Charlotte after being taken with the No. 40 pick in the 2009 draft.
Brewer didn't appear in a game for the Knicks after he was acquired from Minnesota in the three-team, Carmelo Anthony trade. The former lottery pick from Florida will have a chance to sign on with another contender.