Jun 05, 2010 4:11 PM EST

Mariners right-hander Doug Fister will miss his scheduled start Saturday against the Angels with tightness and fatigue in his shoulder.

Fister has the second-best ERA in the American League.

Seattle manager Don Wakamatsu said Friday that Fister's velocity was down Monday when he allowed five runs in seven innings in a loss to the Twins.

Fister is 3-3 with a 2.45 ERA this season.

He is on pace to throw almost 240 innings.

Via ESPN