Henry Owens was demoted to Double-A Portland.
The former prospect had walked 60 batters in 69 innings in Triple-A Pawtucket, striking out 72 with a 3.91 ERA.
“Two of the last three times out, the number of walks have been uncharacteristically high,” Red Sox manager John Farrell said. “Even for Henry.”
Owens had walked 20 in 22 innings with the Red Sox last year. He has a career walk rate of 4.7 walks per nine innings in the minors.
Farrell said the 6-foot-6 left-hander will begin tinkering with a lower arm slot in Portland in attempt to help his command.