Kelce has been contemplating retirement the past several offseasons but has decided to play for at least another year even though the Eagles are going through a transition period.
The reworked deal contains $9 million in guarantees and can be worth up to $12 million, a source told ESPN. Although there are multiple years to the contract, it will function essentially as a one-year deal and offers Philadelphia cap relief for 2021.
"I'm really fired up to be able to come back and play for the Eagles again," Kelce said, via the team's website. "I've always said I'm playing until I'm not and I still have a very strong desire to play the game of football. I still want to do it. I still want to be around the guys. I want to be around the building, around the coaches. I still enjoy that aspect of it and I'm not ready to stop doing it yet. I'm excited with a lot of the energy going around right now and, also, I didn't want to end my career on a season like we had last year. It wouldn't feel right.
"I want to leave the Eagles knowing that I left it in good hands."
Philadelphia entered this week projected to be approximately $40 million over the cap. It also reworked the contract of cornerback Darius Slay, a source confirmed to ESPN, and that reportedly will free up about $9 million.
Kelce's return is big for new Eagles coach Nick Sirianni, who takes over a team that went 4-11-1 last season and was hit hard by injuries. Kelce was the one constant on an offensive line that had an NFL-record 13 different groupings over the first 14 weeks.
He has quietly put together a résumé worthy of Hall of Fame consideration. Kelce is a three-time first-team All Pro and has made the Pro Bowl four times while serving as a team leader, including during Philadelphia's 2017 championship run.
"I'm having fun and as long as I'm having fun and I feel I'm playing at a level I want to play at, I'm going to keep doing it," Kelce said. "I'm looking forward to what's ahead for us."
NFL Network first reported details of Kelce's reworked contract.