By Brian McTaggart

The Astros have agreed to a long-term contract extension with popular second baseman Jose Altuve, a source told MLB.com on Saturday. The deal marks the team’s first significant contract commitment under general manager Jeff Luhnow. Terms of the deal aren’t known, but it will be announced later Saturday.

Luhnow spent most of his first year on the job trading away players who were in the midst of multi-year contracts in exchange for prospects as the Astros went full-bore in their plan to rebuild through the Draft and player development. The Astros opened this year with a payroll of about $22 million, with Bud Norris ($3 million) as the highest-paid player.

Ken Rosenthal of FOXSports.com reports Altuve deal is worth $12.5 million for four years with two club options for $6 million and $6.5 million in 2018–19.

The Astros buying out Altuve’s arbitration years by signing him to the deal. He was scheduled to be arbitration eligible next year and a free agent following the 2016 season.

Altuve, 23, was promoted from Double-A Corpus Christi in 2011 after the Astros traded Jeff Keppinger and plugged into the starting lineup. He batted .284 with three homers and 28 RBIs in 85 games as a rookie before a breakout season in 2012, when he hit .290 with seven homers, 37 RBIs and 33 steals en route to an All-Star Game berth.

He is hitting .280 with three homers, 28 RBIs and 21 stolen bases in 86 games this year.