Source: Cards acquire John Lackey

— -- The Boston Red Sox have traded veteran pitcher John Lackey to the St. Louis Cardinals for outfielder Allen Craig and right-hander Joe Kelly, multiple sources have confirmed to ESPNBoston.com's Gordon Edes.

The deal was reported earlier Thursday by CBS Sports.

It was the second deal completed prior to Thursday's non-waiver deadline by the Red Sox, who also traded All-Star pitcher Jon Lester to the Oakland Athletics for slugger Yoenis Cespedes.

Lackey, 35, should strengthen a Cardinals rotation that has been short-handed due to injuries to Michael Wacha and Jaime Garcia. He went 11-7 with a 3.60 ERA in 21 starts this season -- his fourth with the Red Sox.

Lackey will make just $500,000 in 2015 due to a unique clause in his five-year, $82.5 million contract that tacked on an extra season if he underwent Tommy John surgery at any point. Lackey had the procedure in 2011 and missed the entire 2012 season.

The Cardinals, who entered Thursday just 2 ½ games behind the first-place Brewers in the NL Central, also bolstered their rotation Wednesday with the acquisition of Justin Masterson from the Indians.

Craig was an All-Star in 2013 and one of St. Louis' top hitters over the past few seasons. But the 30-year-old Craig struggled mightily this season, batting a career-low .237 with seven home runs and 44 RBIs in 97 games.

The departure of Craig likely means that promising 22-year-old Oscar Taveras likely will see more time in right field for the Cardinals.

Kelly, 26, is 2-2 with a 4.37 ERA in seven starts this season. He missed nearly three months with a hamstring injury and has struggled in four starts since returning from the disabled list.

Kelly figures to join a completely overhauled rotation in Boston, where the Red Sox will be looking for replacements for Lester, Lackey and Jake Peavy, who was traded to the San Francisco Giants last week.

ESPN Insider Jim Bowden contributed to this report.