CLEVELAND — A sign at the ballpark has turned into a popular T-shirt and charity fundraiser for Mike Napoli and the Cleveland Indians.

It started when a fan brought a “Party at Napoli’s” sign to an early season game at Progressive Field. The slogan took off in the form of T-shirts sold in the team’s gift shop, and Napoli matched a portion of the proceeds for donation to several charities in the area.

Napoli presented a check to Cleveland Clinic Children’s Hospital during a ceremony before Sunday’s game against Miami.

“I enjoy it because I’m able to give back,” Napoli said. “It means a lot for me to be able to do that.”

The T-shirts quickly became a hit with Napoli’s teammates, who wear them in the clubhouse. The fans picked up the trend and the shirts are seen daily in the stands.

“It’s pretty cool to see people wearing them,” Napoli said. “We’re having a lot of fun with it.”

Napoli signed a one-year contract in January, providing a power bat and experience in the middle of the lineup. His production is a big reason Cleveland has led the AL Central since June 4.

Napoli is batting .257 with 29 homers and 89 RBIs, both team highs.

“He’s been a blessing for us,” manager Terry Francona said. “Not just in the batter’s box, but in the way he goes about playing the game. I just think that when you get guys that are really special, you ought to enjoy it because he’s a pleasure.”