The Baltimore Orioles activated right-hander Cesar Valdez from the 10-day injured list on Sunday.
In a corresponding move, the Orioles optioned rookie right-hander Isaac Mattson to Triple-A Norfolk.
Valdez, 36, had been sidelined since June 21 with a lower back strain. The Orioles closer earlier this season, Valdez is 2-1 with a 5.74 ERA and a team-leading eight saves in 12 chances over 25 appearances.
Mattson, 25, has a 4.50 ERA in two appearances this year. He gave up one run over two innings of relief.
–Field Level Media