Boston's entire roster made the trip; The Celtics lead the best-of-seven series, 2-0.
During Wednesday's practice at the Sports Authority Training Center in Waltham, Celtics coach Doc Rivers said that Shaq's ability to travel would suggest he might be able to play again as early as Sunday's Game 4 in New York.
"I'm not sure yet [if Shaq will travel]," Rivers said Wednesday. "It depends on what's best. If he's closer to playing -- you know how we’ve done it -- if you see him on the trip he’s really close."
Later, Rivers added: "If he goes on the trip, that means we think he'll play that Sunday."
O'Neal appeared in 37 games for the Celtics this season, plagued by injuries to the right side of the body, particularly the knee, calf, and Achilles. The 39-year-old center has played only 5½ minutes since Feb. 1.