From Pravda:

Unless something really strange happens, like he gets traded for the third time in about a month, left-hander Garrett Olson will arrive in Arizona in a couple of weeks and compete for one of the 11 spots on the Mariners' Opening Day pitching staff.

Seem benign? Let's isolate the good part and add extra emphasis

 compete for one of the 11 spots on the Mariners' Opening Day pitching staff.

I've long been saying that with a bullpen's fungible nature and value that there's little reason to hold seven of them up on the big league squad when that roster spot could go to a useful additional bench role like a dedicated lefty masher, or allow you to use a platoon at an extra position.

It gives you a five-man bench. It typically takes four spots (catcher, middle inf, corner inf, outfield) just to have replacement at each position, leaving you to force those backups to also cover such roles as pinch runner, LOOGY pinch hitter, ROOGY pinch hitter, etc. That typically means that you have to sacrifice on some of those categories in the name of flexibility. An extra man on the bench means you can specialize a little bit more and as Econ 101 will teach you, specialization will reap you benefits.

The only thing that gets in the way of this is Minor League options and we do have quite a bit of mediocrity on the roster right now that does not have options. That inhibits the creation of a perfectly fluid shuttle between Triple-A and the big leagues, but it is still workable as it stands now. Furthermore, I would expect some of that mess to be cleared away by the end of Spring Training. If Zduriencik and Wakamatsu are committed to trying and sticking with an 11-man staff this year, that would be just one more feather in their cap.