By Steve Ginsburg

MIAMI (Reuters) - Udonis Haslem may not get the same acclaim afforded to his "Big Three" team mates at the Miami Heat but the power forward could still be one of the keys to his team's chances of winning the NBA Championship.

The 30-year-old Haslem has been a source of inspiration to the Heat since returning to the line-up following a painful foot injury that should have sidelined him for the season.

"So anything that he's been able to contribute is an overwhelming bonus. It is a surprise.

"It speaks to his championship heart. He has something inside of him that most players don't have."

Haslem has not only made it back on the court, he has taken on the difficult assignment of guarding Dallas Mavericks' 10-time All-Star Dirk Nowitzki, who is four inches taller than the 6-foot eight-inch tall Haslem, in the NBA finals.

Haslem forced Nowitzki into a sub-par seven-for-18 shooting performance in Miami's 92-84 victory Tuesday in the series opener, while adding seven points and six rebounds himself.

"It's improbable that he's even contributing this many minutes," Spoelstra said of Haslem.

"My plan was just to have him around at the beginning of the playoffs, just to have him in uniform to hear his voice as our team captain. I thought it would be great in the huddles."

Undrafted out of the University of Florida in 2002, Haslem has played his entire NBA career with the Heat and was a member of the team that won the franchise's first championship in 2006.

He said there were times during his injury layoff that he feared he may not be back this season but the prospect of joining Lebron James, Dwyane Wade and Chris Bosh in the finals provided all the motivation he needed.

"I knew I was going to be in some pain when I decided to come back," he said. "And I'm willing to deal with it to get this ring.

"There were times this year I didn't quite feel like myself. My teammates were just keeping me involved, keeping me encouraged.

"And when I was able to get back in and be a part of this physically, I was able to be myself again as far as being vocal and being an inspiration leader to these guys."

(Editing by Julian Linden)