The Oakland A’s will sign former Arizona Diamondbacks third baseman Jake Lamb, multiple sources close to the situation told this news organization Saturday night.

The A’s hope that Lamb, an All Star in 2017, can help offset the loss of Matt Chapman, who will have season-ending hip surgery Monday after having missed the past week. The signing isn’t official yet, he won’t be a free agent and able to sign until Monday, but Lamb will be eligible for postseason play as he would be joining the team prior to the Sept. 15 deadline.

Lamb, 29, has had a rough start to his seventh season with the Diamondbacks. He slashed .116/.240/.140 and a .380 OPS with 17 strikeouts and no home runs in 18 games.

In his All Star season, Lamb had 30 home runs and 105 RBI. (Slash line: .248/.357/.487 with an .844 OPS.) He had 29 homers and 91 RBI in 2016 with a slash of .249/.332/.509 and an .840 OPS.

With Chapman out and Chad Pinder potentially hitting the IL with a strained hamstring, the A’s options at third base were Vimael Machín and Tommy La Stella.

The A’s also had Sheldon Neuse as an option at the A’s alternate site in San Jose. But, with the postseason looming, finding more depth at the position was imperative.

In Lamb, the A’s will get another left-handed batter to complete a now very left-handed crew that features La Stella, Tony Kemp, Matt Olson and switch hitters Jonah Heim and Robbie Grossman.