CHICAGO – When Nikola Pekovic left the United Center court midway through the first quarter Monday night because of a sore right Achilles' tendon, it was the culmination of a very painful week.

"I've been having the same problem the last week," said the Timberwolves center, his right foot calf-deep in ice water after the 95-86 victory over the Bulls. "The last three games I played with that, and I was kind of suffering. It hurt, but I was trying to get through it."

Pekovic, who is averaging career highs in points (18.4), rebounds (9.3) and minutes (33:06) per game, has remained healthy all season. But, in recent days, the pain in his heel — he described it as a bruise — became too much.

"That's been bothering Pek the whole trip," coach Rick Adelman said. "We haven't said anything about it and he hasn't said anything about it."

Pekovic tried to play through the pain. But it was clear after just a few moments Monday he couldn't go. "After the back-to-back [Friday and Saturday at Golden State and Portland] it got really, really bad," he said. "And [Sunday] I was in pain."

So now the question is how long Pekovic will be out of action. He will see a doctor Tuesday morning for further tests, after which a timeline for his return might be set.

"I don't know anything for now," he said. "I hope it's nothing serious. I hope."

Rubio picks it up

Wolves President of Basketball Operations Flip Saunders doesn't have to look at the stat sheet to see whether Ricky Rubio is himself or not. Saunders can see it in the point guard's face and body language.

It wasn't long ago that Rubio, struggling, talked about trying to find himself.

"He's had good enthusiasm of late," said Saunders, who was with the team in Chicago. "He's been leading. He has just been more himself, getting into the game a little more, both defensively and offensively. Basically, he's just having fun again."

Rubio entered Monday on one of his best three-game streaks in a Wolves uniform. In games at Utah, Golden State and Portland, he made 11 of 20 shots (55 percent), averaging 10.0 points, 12.0 assists, 3.7 steals and 3.0 rebounds in those games.

Rubio, who had nine points, six rebounds and four assists Monday, said he started feeling better even before his recent three-game run.

"The last four or five games have been better," Rubio said. "I have found my rhythm, and I'm feeling pretty confident. I just have to keep doing what I'm doing."

Rubio is also making baby steps toward being a scoring option at crunch time. When he made a fall­away jumper with 1 minute, 55 seconds left in a 121-120 victory at Golden State on Friday, it was his first fourth-quarter points since Dec. 16. In the 16 games before that, he was 0-for-10 in the fourth quarter.

"I just have to keep working," he said. "I knew the things were going to come. I knew how I could play."

Back in Chicago

Monday's game was Chase Budinger's first in Chicago since Nov. 10, 2012, when he initially tore the meniscus in his knee.

That injury, which came in the sixth game of the season, set in motion a 14-month odyssey for the Wolves swingman. He had his initial surgery and returned to play in the final 19 games of last season. He experienced difficulty in the knee and had to have a second procedure before camp began last fall, keeping him out of action until this month. Monday's game was his 10th game back.

"It was just last season," Budinger said of the injury, which came in a fourth-quarter scrum under the basket. "It feels like a lot longer."

Still, he said, having come back from two surgeries has made him stronger.

"Knowing I can come back from this, I can come back from anything," Budinger said. "Especially mentally. Last season it was tough staying positive, staying engaged in everything. It really showed me how much I loved the game of basketball being away from it."