The right-hander agreed to an $82.5 million, five-year contract with Boston in December 2009 that contained a provision for a conditional team option at the minimum if he missed a season due to specified injury. Lackey did not pitch in 2012 after reconstructive elbow surgery.
The major league minimum next year will be $500,000 plus a cost-of-living adjustment to be determined Nov. 20, which is likely to be $9,000 to $10,000.
Lackey, who turned 36 on Oct. 23, was 14-10 with a 3.83 ERA last year with the Red Sox and Cardinals and was 1-0 in two postseason starts for the NL Central champions.
He was acquired at the trade deadline in July in a deal that sent outfielder Allen Craig and pitcher Joe Kelly to Boston. Cardinals general manager John Mozeliak said the contract option was a key to the deal.
Cardinals Exercise Lackey's Option
ESPN senior baseball writer Jerry Crasnick discusses the Cardinals' decision to exercise their 2015 contract option on pitcher John Lackey, which is at the major league minimum.