The Mariners sent Jeff Weaver to the DL with shoulder tendinitis, and not a moment too soon:

The Mariners are among the lighter opponents on the schedule, but their record is better than the Yankees, who are 16-18. Seattle is 16-15, but 16-9 in games not started by Jeff Weaver, who landed on the disabled list Friday with shoulder tendinitis.

Weaver was so bad, if the Mariners had signed almost anyone else, if they just called up a AAA starter, they're probably in first place right now.