WALTHAM — After Game 4, LeBron James said it was time to “explore” having him guard Rajon Rondo. On Monday in Cleveland, Cavs coach Mike Brown said it was likely going to happen.

That’s fine with the Celtics who have been waiting for this to happen since the series started.

“We don’t care who guards Rondo,” Doc Rivers said Monday. “We’re going to still run out stuff. It’s not like we’re going to stop running our offense. We anticipated it. I’ve only talked about it for three games. We know it’s going to come at some point in this series. When it does we have to find a way of using Rondo and making sure he’s still the facilitator.”

Rivers felt that one of the keys in Rondo’s huge Game 4 performance was that he made things happen off ball movement. This was a key difference from Game 3 when most of the Celtics offense came off one-on-one isolation plays (or rather breakdowns).

Rondo, who sees more gimmick defenses and adjustments than any of the other Celtics combined, isn’t worried about it either.

“It’s happened before,” Rondo said. “LeBron is going to be LeBron. He’s a great help-defender so he’s definitely going to be helping. He’s a good defender. They did that a couple of years ago when Kobe [Bryant] was checking me in the Finals. So, I’m used to bigger guys giving me the shot and challenging me late because of their wingspan.”

Brown has resisted employing the LeBron option to this point and a good reason for doing so is that James has taken Paul Pierce out of the series to this point. If he does take Rondo, that would put Anthony Parker on Pierce, and while Parker is a good, veteran defender, he’s no nearly as physically imposing as James.

“That’s probably one of the reasons they haven’t,” Rivers said. “But they’re going to at some point. It may not be all game. It may be in the fourth quarter. It may be in the second half, out of timeouts. And will be ready for it.”