The Orioles announced Saturday afternoon they were making a rare intra-divison trade. Cashner, 32, is 9-3 with a 3.83 ERA in 17 starts this season. He is on pace to surpass his career-high in wins -- he went 11-11 with the Texas Rangers in 2017 -- and was one of the few bright spots on a dismal Orioles team.
"It's a shocking moment, but I kind of saw it coming, just the way our club is trending," Cashner said Saturday. "I think it will maybe sink in tonight and once I leave tomorrow."
Cashner is expected to take Nathan Eovaldi's place in the starting rotation. Eovaldi, who signed a four-year, $68 million contract with the Red Sox last December, is expected to become Boston's closer.
"He's a guy that's taken the ball and given six, seven innings on a consistent basis, so we like a lot of the things about him," Red Sox general manager Dave Dombrowski said. "We think he makes us better."
Cashner is 55-82 with a 4.00 ERA since debuting with the Chicago Cubs in 2010. He will hit free agency after this season.
The Orioles acquired infielder Noelberth Romero and outfielder Elio Prado from the Red Sox. Both will report to the Dominican Summer League, where the Orioles have two teams.
Baltimore is 28-54 this season. The Red Sox are 50-42 and 1 1/2 games behind the Oakland Athletics for the American League's second Wild Card spot.