Bass did not allow a baserunner over 1.1 innings, striking out two batters and earning the save in Friday's 4-3 win over the Angels.
It's the journeyman reliever's first major-league save since 2014. Bass has done well in five appearances since signing with the Mariners, with a 1.42 ERA and 0.63 WHIP in 6.1 innings. He's not expected to compete for saves, but the right-hander may be trusted with higher-leverage assignments if he continues to pitch well.