Right-hander Mitch Keller and the Pittsburgh Pirates are in agreement on a five-year, $77 million contract extension, sources tell ESPN, locking up another young core player as the team continues to try to return to the postseason for the first time in nearly a decade.

The deal, which begins this year and ends after the 2028 season, will pay Keller $7.5 million in 2024 -- more than $2 million above where he had settled with the team in arbitration, according to sources. In what would've been his final year of arbitration in 2025, Keller will receive $15 million. For the three free agent years the Pirates bought out, they will pay Keller $16.5 million, $18 million and $20 million.

Keller, 27, had a breakout 2023 season in which he was an All-Star for the first time and struck out 210 in a career-high 194 innings, anchoring a rotation in which he soon could be joined by Paul Skenes, the No. 1 pick in last year's draft.

Keller, who was set to hit free agency after the 2025 season, is the third core member of the Pirates to receive an extension. Third baseman Ke'Bryan Hayes and outfielder Bryan Reynolds both signed deals in recent years that can go through at least the 2030 season.

A hard-throwing right-hander Pittsburgh chose in the second round out of an Iowa high school in 2014, Keller was a top prospect but struggled at the outset of his career. He turned it around in 2022 and got a lot of work in 2023, finishing fourth in the National League in innings pitched last season with a nearly 4-1 strikeout-to-walk ratio.

The Pirates got off to a hot start in 2023 but faded down the stretch, finishing 76-86 and in fourth place in the NL Central. They signed a slew of veterans this winter, including reliever Aroldis Chapman, left-handed starter Martin Perez, first baseman Rowdy Tellez, catcher Yasmani Grandal and longtime franchise icon Andrew McCutchen.

Keller, who was 13-9 with a 4.21 ERA last season, is 25-38 with a 4.71 ERA in 102 career appearances (100 starts). He has 521 strikeouts in 523 innings.