A 13-year-old cancer patient who threw out the first pitch at a Nationals game earlier this season and was an inspiration to Bryce Harper has died after his three-year battle with the disease, the Washington Post reported today.

Gavin Rupp, who came to Nationals Park on July 5, reportedly made quite an impression on Nationals star Bryce Harper after speaking to him for nearly an hour before the game that day. Harper gave Rupp a signed hat, baseball and mitt and then handed him a baseball and asked Rupp to sign it for him.

"I'll put this in my locker," Harper said after taking the ball, according to MLB.com.

Harper later held up Rupp's name on a placard as part of MLB's "Stand Up 2 Cancer" campaign at the Home Run Derby.

After hearing the news, Harper tweeted: