The seven-time All-Star had microfracture surgery on his left knee in February, but insisted before Friday night's game against the streaking Atlanta Hawks that he's fully recovered.
"Right now, I could play," he said.
Not so fast. The Rockets believe McGrady needs more time and would risk hurting his knee again if he comes back too soon. The next step is an MRI exam on Monday.
"We have a difference of opinion," coach Rick Adelman said. "He wants to play. He's not ready to play. It's as simple as that."
Both sides denied a Yahoo! Sports report that the situation degenerated into a heated argument before the Rockets' previous game at Minnesota. The report quoted a person close to McGrady who was not identified.
"I don't know where that came from," McGrady said. "We talked but it was nothing that was reported like that. I mean, screaming and all."
Adelman shrugged off the report as "our world of the Internet."
"It seems like nowadays people want to dwell on one particular thing that may be newsworthy," he said. "Or maybe catch your eye when you look at it."
Whether the argument actually happened, it's clear that McGrady considers himself much further along in his recovery than the team's timetable.
"I don't know," he said. "It's all about what they want to do."