Back in March, Jim Kelly announced that his cancer had returned. The Bills legend and Hall of Famer was first diagnosed in 2013, when doctors gave him just a 10 percent chance to live. The cancer "came back with a vengeance" a year later and it returned once again this spring. 

Kelly, 58, endured a 12-hour surgery in late March that removed the oral cancer and reconstructed his upper jaw. And now, according to Kelly's wife, Jill, he will undergo another surgery on Thursday.

"Back in the Big Apple for more surgery today," Jill Kelly wrote on Instagram. "Another step forward in the healing process. If all goes well, we will be back home by the weekend. Other than God's Grace and a whole lot of praying ... I don't know how he does it.

"Like Hunter's life, Jim's struggles are a constant reminder that this life is not the end of the story," she continued. "God's plans are eternal. And He's just getting started. We have so much to look forward to! There is immeasurably more waiting. ... Thank you for praying! Wish I could hug you and thank you in person."

Jill and Jim's son, Hunter Kelly, died in 2005 at the age of 8 of a nervous system disease.

Kelly said earlier this year that he draws inspiration from those who have said they've been inspired by his journey.

"I want them to know that they inspire me to never give up," he said. "Because if I can make a difference for you, I know what you've done for me. I live by this motto: Make a difference today for someone who is fighting for their tomorrow."

"I might have lost four Super Bowls in a row, but I've kicked cancer's (butt) twice," Kelly told the Buffalo News' Vic Carucci during a March phone interview. "And I plan on making it a third, with the grace of God."