Oakland Athletics right-hander Sonny Gray was placed on the disabled list Sunday due to a strained right forearm.
Gray departed Saturday's loss to the Chicago Cubs after five innings due to forearm soreness. The diagnosis was confirmed Sunday after a battery of tests.
The DL stint will be the second of the season for Gray, who is suffering through the worst year of his career. He is 5-11 with a dismal 5.74 ERA.
Gray won 14 games in each of the previous two seasons and was an American League All-Star in 2015. He finished third in AL Cy Young Award balloting last season.
Smith made 50 career relief appearances for the Boston Red Sox and Brewers from 2008-10 and went 1-0 with a 5.19 ERA.
Catcher Josh Phegley (knee) was transferred to the 60-day disabled list to open up a 40-man roster spot for Smith.