Left-hander Ryan Rowland-Smith was activated from the 15-day disabled list Friday.
Rowland-Smith went on the DL July 28 with a lower back strain. He has made five rehab starts at Triple-A Tacoma. Thursday against Colorado Springs, he allowed one earned run in seven innings with five strikeouts.
Rowland-Smith was expected to be the Mariners' No. 3 starter after a promising 2009 season, but he struggled mightily. He went 1-10 with a 6.96 ERA in 22 appearances, including 19 starts. In his last start a day before going on the DL, he gave up a team-record 11 runs on 11 hits in 5 innings to the Chicago White Sox.
After that shellacking, Rowland-Smith gave no indication that he was injured, instead blaming his control for his struggles.
"Just leaving the ball up quite a bit and it cost me," he said.
He is available for tonight's home game against the Cleveland Indians.