MIAMI – After Friday's 117-104 loss at Miami all but ended the Timberwolves' playoff aspirations, coach Tom Thibodeau demanded more of his best players and promised he'll "drive" his team through the tape 14 games from now.

"There's not going to be a letup," he said.

But how much can he ask of young stars Andrew Wiggins and Karl-Anthony Towns, who already are third and sixth respectively in the NBA in minutes played?

Only Toronto's Kyle Lowry and Cleveland's LeBron James have played more than Wiggins' 37.2-minute average. Only those three, injured Wolves guard Zach LaVine and John Wall have played more than Towns' 36.8 average.

After the Wolves allowed the Heat to shoot nearly 59 percent Friday, Thibodeau said he wants not more minutes, but better preparation, more intensity, improved defense and "maximum effort and maximum concentration" from everybody, particularly his best two players.

"Our leaders have to lead," he said. "They have to play defense. There are a lot of guys who can get stats and lose. That's meaningless."

Wiggins' shooting statistics have slipped in March to 35.5 percent (54-for-152) after he shot 51.4 percent in February. He said neither his recent offense nor the lack of the kind of defense Thibodeau sought Friday can be attributed to tired legs, swarming defenses or too many minutes played.

"Nah, that's me," he said. "I'm missing layups and all kinds of stuff. I would say that's just me. I'm all right. I feel good. I'm just ready for the games, really."

Towns' franchise-best streak of consecutive 20-point games ended at 21 games when he scored 17 in Boston on Wednesday, but he potentially started another with a 31-point night Friday in Miami. That's his third 30-point game in the past four games and his 15th this season.

Thibodeau seeks that kind of energy and effort on the floor's other end every night. But if he didn't get it Friday in Miami or Wednesday in Boston, it's not because of late-season fatigue.

"I feel real good," Towns said. "I put a lot of work in this offseason not only on my game, but my body to withstand whatever is thrown my way. I feel if we'd have a deep playoff run and get to the Finals, that would be fine. I have my body prepared for that. I feel very comfortable. I've very glad and very blessed to have a body like that."

When asked if Wiggins' recent shooting slump is because of tired legs or body, Thibodeau answered with three words.

"No, no, no," he said.

He said Wiggins has been taking good shots, makeable shots. What he needs to do is know and accept such things happen.

"You're not going to shoot great for all 82 games," Thibodeau said. "But you can play well when you don't shoot well, and that's what I want him to understand. You have to do other things: Get to the free-throw line, get some scores off your defense. He's really athletic, so deflect, steal, run, get into the open floor, get some easy buckets."

Wiggins turned 22 last month, Towns still is 21. If they are feeling any fatigue in a season when they've been asked to do so much, well, they're not alone.

"Look, 68 games into a season, everyone's feeling the same thing this time of year," Thibodeau said. "Mentally, you have to be strong. You have to be able to deal with the length of the season, and that's what you should be preparing for year round and that's why your offseason is so important, that's why lifting is so important, why conditioning is so important. There are going to be some ups-and-downs during the season."

Wiggins said he and Towns know what Thibodeau is asking from them and the kind of responsibility they have to make the Wolves winners, even at such a young age.

"We have a lot, a lot more responsibility that last year or the previous year," Wiggins said. "I feel like we're ready for it. You know we're taking on the challenge."