Griffin - the 27-year-old brother of Clippers All-Star Blake Griffin - is still recovering from an ankle injury suffered during last years D-League playoffs and has yet to appear in any games this season.
He started 44 games for Santa Cruz last year averaging 10.7 points, 6.5 rebounds, 1.9 assists and 1.2 steals per contest.
Taking the vacant roster spot is McGuire who plays both forward positions and even shooting guard. The 28-year-old has played in 342 NBA games since 2007 with the Wizards, Kings, Bobcats, Warriors, Raptors, Hornets and Pacers averaging 2.7 points, 3.4 rebounds and 1.2 assists per game.
He was cut after spending training camp with Utah this preseason.
According to Santa Cruz's Twitter account, McGuire will wear No. 18 and be available for tonight's home game against the Canton Charge.