Valencia resident Dan Sheehan gives thumbs up while riding in the Pan-Mass Challenge a number of years ago. Sheehan was scheduled to return this year to the annual August bicycling event that fights cancer, but will miss the ride with a knee injury.

VALENCIA — Dan Sheehan is out of the game— temporarily.

The stakes are too high to remain on the sidelines permanently.

Sheehan, 55, of Valencia, was scheduled to return to the Pan-Mass Challenge (PMC) in Massachusetts, a bicycling event Aug. 4-5 designed to raise money for critical cancer research and patient care at the Dana-Farber Cancer Institute.

Sheehan was a longtime resident of central Massachusetts before moving to Valencia five years ago. He lost his father to cancer.

“Some of my family members started riding for him and I joined in,” Sheehan said. “Other family members on my wife's side and mine have dealt with cancer and I ride for them, too.”

This was scheduled to be Sheehan's ninth ride in the PMC, but his first since 2009.

“Some friends got me back into it,” he said.

Sheehan registered for the PMC last winter. He will not be able to participate in next month's ride, however, as he tore a meniscus in a knee playing tennis three weeks ago.

Once he registered, he became committed to raising $4,900 for the Farber Cancer Institute.

Sheehan's ride would have been 192 miles, beginning in Sturbridge, Mass.

“That's a preferred route and there will be 3,500 riders or more starting from that point,” he said.

The PMC's goal is to raise $52 million for the fight against cancer through this year's ride. More than 6,200 cyclists from more than 40 states and seven coun tries will gather in Massachusetts for this event.

This the 39th annual PMC bike-a-thon — founded by current executive direcrtor Billy Starr —which has raised more money for charity than any other single athletic fundraising event in the world.

“We are excited to keep the momentum going,” Starr said in a released statement. “We are continuously humbled by the dedication and generosity of our riders, volunteers, donors, sponsors and community members.”

Riders range in age from 15 to 84 and include everyone from seasoned triathletes to weekend warriors.

Last year's PMC raised $51 million and the PMC has raised $598 million in its history.

“One hundred percent of that money goes to Farber,” Sheehan said. “I'm still in the process of raising my $4,900, but that's OK. It's a dynamite cause.

“We have what we call 'pedal partners,' children with cancer, and we ride for or with their families. It sends a powerful message.”

Sheehan raises funds through postcard mailings, social media, family and friends. He encourages people to look into the PMC.

“Anyone can donate at pmc.org,” he said. “Looking for a cure for cancer ... It's all good stuff.”

Now that he's involved in the PMC again, Sheehan says he won't let it go.

“I'll ride as long as I'm physically able,” he said.