Ray Allen said he honestly doesn't know if his career will extend past this season.

"It's really hard to say, realistically," Allen said Friday. "A lot has to to with the circumstances that we have in front of us here."

Allen opted in for a second season with the Miami Heat, who are seeking a three-peat as NBA champions. At 38, he he's focused on the present.

"I know the way my body feels. It's really how much I decide to push myself and continue to push myself and put myself in unique situations and figure out how my body can overcome challenges, getting older and recovering," he said. "I just know being out here and doing this is a great challenge every day, getting your body together and getting it to a place I've never seen it.

"You get to the summer and I see how I feel and take it from there."

The Heat will play Allen's previous team, the Boston Celtics, on Saturday night at AmericanAirlines Arena.

The veteran sharpshooter, who also won a title with Boston, was asked if it will be strange to see a Celtics team without ex-coach Doc Rivers and former stars Paul Pierce and Kevin Garnett.

"Emotionally, I'm not connected to that situation," Allen said. "What we do and we think about here, what we focus on here allows me to stay on track.