Having locked up Peters on Wednesday, the team announced contract extensions for Kelce and Cooper on Thursday.
A source informed of the negotiations tells NFL Media Insider Ian Rapoport that Kelce's six-year extension is worth $37.5 million with $13 million guaranteed and an annual average of $6.25 million.
Rapoport reports, via a person who has seen the contract, that Cooper's deal is valued at $25 million over five years, with $8 million fully guaranteed.
Kelce will be paid commensurate with a top-five NFL center, which is appropriate. Still just 26 years old, Kelce is the ideal athletic center for Chip Kelly's up-tempo offense.
The 2011 sixth-round draft pick graded out as Pro Football Focus' No. 1 center in 2013.
According to Rapoport, though, the front office and the wide receiver were hoping for "big progress" over the next two days. There's still optimism on that front.
Signing three core offensive players allows the team's brass to expend its energy and resources on the other side of the ball during free agency and the draft.