ATLANTA -- Even if you are young and healthy and just 19 years old like Justise Winslow, the grind of an NBA season can take its toll.

And the Heat rookie, who turns 20 on March 26, was feeling that grind all over his body before the All-Star break.

"I was definitely not 100 percent going into the break," said Winslow, who missed just three games in the first half with an ankle injury and ranked fifth among all rookies in minutes played (27.8 per game).

"The break was much needed."

At 6-7, 225 pounds, the Heat ended up using Winslow a lot more at power forward than most expected -- especially down the stretch of games when Hassan Whiteside would go to the bench and Chris Bosh would slide over to center. In fact, no one has played more fourth quarter minutes this season for the Heat than Winslow (9.1 per game).

Now, with Bosh back on blood thinners and no one quite sure when the Heat's leading scorer will return, Winslow's role and overall minutes are expected to expand in the second half. Tuesday in practice, he ran with both the first and second team units and it's likely he could start a lot more games in the second half of the season if Bosh doesn't return.

Starting games, Winslow admitted, was a bit of a challenge for him earlier this season when he was pressed into that duty for three games. And the numbers prove it. He was minus-28 as a starter and plus-67 off the bench.

"Coming off the bench you can get a feel for the game and I think that's a huge advantage," Winslow said. "You know whose hot or how they're playing certain defenses. When you start, you're kind of trying to figure all that out. So when you come off the bench it kind of makes it a little easier to get into the flow of the game.

"[As a starter] I was winded at first. I was coming out too hard. By the third [game], I kind of figured it out. That's how it is every game, both teams are trying to figure the flow of the game. It took me a while to kind of figure that out."

Defensively, Winslow remains one of the best rookie defenders in the league. He's holding opponents two percent under their normal shooting percentage and 41.7 percent overall. It's the offensive side of the game he's still working to improve.

Although he averaged only 5.7 points per game in the first half (19th among rookies) and shot 41.8 percent from the field and 25.8 percent from three-point range, his shooting and offensive production improved over the Heat's final eight games before the break (7.0 points, 54.8 percent from the field) after coach Erik Spoelstra implemented some offensive changes beginning with a game in Brooklyn Jan. 26.

Winslow said Spoelstra has been urging him and others like Goran Dragic to grab the rebound "and push it" like he did last year as a freshman at Duke. Now, with Bosh out, Winslow is eager to do a little more of that to help make up for the scoring punch the Heat will be missing with their leader out.

"One person isn't going to make it all up. It's going to be a collective effort," Winslow said. "Three points here, five points there. It's not going to be one person that makes up 19 points or whatever CB averages. It's about everyone stepping up. He was kind of the voice on the floor. So, everybody has to communicate better. We just have to find ways to pick up some of the things CB did.

"The whole game now without CB it's going to be really tough. But I'm sure we're going to figure out a way."

> Another player for the Heat who will have to see his role expand in the second half is Josh McRoberts.

Dwyane Wade said Tuesday with Bosh out the Heat are going to need more scoring from McRoberts in the second half. That's something McRoberts has never really been comfortable doing in his career as a player. He prefers to set others up.

More than anything, though, the Heat just need McRoberts to stay healthy and on the floor. He's missed 93 of a possible 135 games the Heat have played since he was signed to a four-year, $22.6 million deal in the summer of 2014.

Asked Tuesday if he feels the need to step up his game in the second half so he's not considered a bust, McRoberts shook his head.

"No," he said. "People are going to think what they're going to think one way or another. I'm never going to be a big numbers guy. If that's all people care about, that's never going to change much.

"For me, sure you want everybody to love you. But I just want to come out here and help my team. I didn't choose to be injured. I think that's what people think. I'm more frustrated than everybody else is with being hurt, and with how things have gone. I'm just excited to get back out here and help us get some wins."