The Boston Red Sox have traded right-hander John Lackey to the St. Louis Cardinals for right-hander Joe Kelly and outfielder Allen Craig before Thursday's deadline, a person with knowledge of the deal said.
The person spoke on condition of anonymity because neither club announced the trade.
Earlier, the Red Sox sent their top starter, left-hander Jon Lester, to the Oakland Athletics with outfielder Jonny Gomes and cash for slugging outfielder Yoenis Cespedes and a 2015 draft pick.
Lackey was 11-7 with a 3.60 ERA as the No. 2 starter in Boston's rotation.
Kelly is 2-2 with a 4.37 ERA in seven starts.
He has made four starts since being activated from the disabled list on July 11.
Craig is batting .237 with seven homers and 44 RBIs.