Cardinals acquire Zach Duke from White Sox

The Cardinals have acquired left-hander Zach Duke from the White Sox for outfielder Charlie Tilson, according to a team announcement.

The move is the first deadline deal for the Cardinals, who were known to be in the market for relief arms and still could add another. The White Sox are expected to sell many pieces before Monday’s deadline, with Duke being the first to go.

Duke, 33, has posted a 2-0 record and 2.63 ERA in 37.2 innings spread over 53 appearances with Chicago this year. He will join left-handers Kevin Siegrist, Tyler Lyons and Dean Kiekhefer as lefties in the Cardinals’ bullpen mix.

Duke is in the second year of a 3-year, $15 million contract, and will be owed $5.5 million in 2017. His addition comes a year after St. Louis added Steve Cishek and Jonathan Broxton to its bullpen mix for the stretch run.

Tilson, 23, was the Cardinals’ 2nd-round pick in the 2011 draft and is currently ranked by MLB.com as the 12th-best prospect in their system. He is a speedy plus-hitter who has posted a .282/.345/.407 line with 15 stolen bases for Triple-A Memphis so far this season.

Tilson led the Texas League with 159 hits and 46 steals in 134 games last season at Triple-A Springfield.