The Mariners outrighted Devenski off the 40-man roster and assigned him to Triple-A Tacoma on Tuesday.
The 33-year-old has been with Tacoma since signing a major-league contract with Seattle in early July, and he pitched well in six outings with two earned runs allowed and a 5:0 K:BB over 5.1 innings. Devenski is likely losing his place on the 40-man roster to make room for trade-acquisition Justin Turner.