PITTSBURGH — The Pittsburgh Pirates and All-Star pitcher Mitch Keller agreed to a five-year contract worth $77 million, a person with knowledge of the agreement told The Associated Press on Thursday.

The deal is pending a physical, the person said on condition of anonymity because the agreement was not yet final.

The contract, the largest the Pirates have given a pitcher, begins this season and runs through 2028. It replaces a one-year agreement last month worth $5,442,500.

Keller would have been eligible for free agency after the 2025 season.

A 27-year-old right-hander, Keller is coming off a breakthrough season in which he became a first-time All-Star. He finished 13-9 with a 4.21 ERA on a Pirates team that went 76-86..

The agreement figures to give Pittsburgh some long-term stability at the top of the rotation as they try to move closer to contention in the NL Central following a methodical top-to-bottom overhaul that began when the team hired general manager Ben Cherington in the fall of 2019.

The deal is the last in a series of moves in recent years to lock down players the team considers the “core” of the rebuild. Pittsburgh signed Gold Glove third baseman Ke'Bryan Hayes to a $70 million, eight-year deal before the 2022 season and inked c enterfielder Bryan Reynolds to a $106.75 million, eight-year deal last April.

Keller, a second-round pick in the 2014 amateur draft, endured significant growing pains after arriving in the majors in 2019. He went 7-17 with a 6.02 ERA during his first three seasons and was briefly demoted to the bullpen for a brief stretch in 2022.

The addition of a sweeper to his repertoire and an uptick in velocity has helped Keller become the front-line starter the Pirates have lacked since trading Joe Musgrove to San Diego following the 2020 season. Keller fanned a career-best 210 hitters last year, becoming the first Pirates pitcher to reach 200 since Gerrit Cole and Francisco Liriano in 2015.

Keller likely will be the opening day starter for a second straight year and his presence gives the Pirates someone to build around as they try to put together a staff comprised of largely home-grown talent, a group that includes 2023 top overall pick Paul Skenes and 21-year-old right-hander Bubba Chandler.

While there's a chance Skenes could reach the majors this season, Chandler may be a bit further away. Pittsburgh likely will break camp with a rotation that includes Keller, free-agent signees Marco Gonzalez and Martin Pérez. There's plenty of competition for the final two spots, a group that includes former first-round pick Quinn Priester and Roansy Contreras.