BOSTON (AP) - The Red Sox have promoted infielder Jonathan Diaz and designated right-hander Clayton Mortensen for assignment.
Diaz will make his major league debut Saturday against Toronto, starting at third and batting ninth.
The 28-year old Diaz signed a minor league free-agent deal with Boston in December. He played in 55 games for Triple-A Pawtucket, batting .242 with two homers and 21 RBIs.
Mortensen was 1-2 with a 5.34 ERA in 24 games for Boston this season. He was acquired from Colorado in January of 2012 for shortstop Marco Scutaro. He was designated for assignment to make room on the 40-man roster for Diaz.