Boston Celtics guard Marcus Smart says his left calf injury is “nothing serious.”

Smart is out indefinitely for Team USA and will be re-evaluated by doctors next week when Team USA heads to Los Angeles for the second week of training camp.

Smart, the heart and soul of the Celtics, says he's just being cautious.

“Right now, for me, I’m trying to grow as a player… taking those precautions,” Smart said, via Chris Forsberg of NBC Sports Boston. “Last year, or two or three years ago, I probably would have still been out there trying to fight through it. It’s nothing serious so we just want to make sure it doesn’t turn into anything serious.”

Marcus Smart had a sore ankle on Tuesday and took himself out of Team USA practice as a precaution.

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Last season, Smart averaged 8.9 points, 2.9 rebounds and 4.0 assists for the Celtics while shooting 42.2 percent from the field, 36.4 percent from beyond the arc and 80.6 percent from the free-throw line. He’s joined in Las Vegas by Celtics teammates Kemba Walker, Jayson Tatum and Jaylen Brown. The four went out to dinner on Sunday.

There's no point for Smart to play through pain for Team USA, especially since he's not getting paid to do this.