The Red Sox called up infielder Brandon Snyder in a corresponding move. To make room for Snyder on the 40-man roster, the Red Sox transferred catcher David Ross (concussion) to the 60-day disabled list.
Middlebrooks, 24, has struggled badly at the plate this season, hitting just .192 with a .228 on-base percentage. Both numbers are the worst among everyday third basemen in the majors. Since June 10, after a short stint on the disabled list because of a lower-back inflammation, he has appeared in seven of Boston’s 14 games. Over that span, he has just 4 hits in 29 at bats (.138).
The 23-year-old Iglesias, meanwhile, is batting .426 is 33 games this season.
The 26-year-old Snyder was hitting .267 with 10 homers and 37 RBIs with Pawtucket this season. He will wear No. 13 with the Red Sox.