Fresh from both Jose Romero over at Baker's blog and the official team website, we get the following:

Let's make one thing clear right now: nobody's going to do what Sherrill did last season. The Governor was terrific all summer long, and what this really comes down to is a battle for who the coaching staff thinks can provide the smallest downgrade. To believe anything else is delusion.

There are four nominal contenders for this role, listed above. However, both RRS and Feierabend are (justifiably) viewed as potential long-term starters or swingmen, so they're highly likely to begin the year getting stretched out in Tacoma. I support this decision, because I think RRS has it in him to be the third-best starter in the organization by July. (That's both good and rather damning.)

But meanwhile, barring some surprise, that means we're left with Eric O'Flaherty and Cesar Jimenez vying for the job of #1 lefty. Of all the competitions taking place in Mariner camp this spring, this one stands to be the most important.

O'Flaherty sure as hell better win.

For as long as he was a Mariner, George Sherrill's job was, first and foremost, to pitch against the top lefty hitters in the league. And he succeeded with flying colors. With a .167 BAA and a 34% strikeout rate versus left-handed bats, Sherrill's been one of, if not the premier specialist in baseball. What's the key to his success? That big, sweeping breaking ball. More than anything else, it's been that pitch that's granted him such terrifying power.

For a lefty specialist, the breaking ball is absolutely essential (the same goes for righties vs. righties). By diving and darting away from the hitter, it slows down the bat and makes contact - particularly solid contact - quite difficult. In fact, it's such a good weapon that, against same-handed hitters, pitchers tend to work off the heater and breaking ball almost exclusively. Observe:

Pitch selection of lefty relievers vs. lefty bats:

Fastball: 59%
Breaking Ball: 36%
Changeup: 5%

(We're dealing with lefty relievers here, so they're all I looked at.)

The fastball's always going to be a pitcher's staple, but when going to something else against a same-handed hitter, it's almost always going to be a slider or a curve. Pitchers avoid the changeup in these situations because, unlike a breaking ball, changeups dart back in towards the hitter, which speeds up his bat and comes with an invitation to pull the ball down the line. And obviously the last thing you want to do is give a hitter that kind of opportunity. By and large, the change is used only sparingly in these situations to mix things up. To be more ambitious is to put your job in jeopardy.

Where am I going with this? I'm glad you asked. At this point, Eric O'Flaherty is a known quantity. He's got a three-quarters delivery that unleashes a decent fastball with a bit of sink, a tough, sharp slider, and a developing change. His Major League splits last year were exaggerated - his true talent level isn't a 248-point OPS split between lefties and righties - but he's definitely well-suited for the kind of work for which he's competing. He has good command of his slider, and it's a legitimate weapon against tough lefties.

Cesar Jimenez, on the other hand, doesn't fit the profile at all. While the organization really seems to like him for whatever reason, this isn't the right role for his skillset. Jimenez also uses a three-quarters arm slot, but his fastball is a few ticks below O'Flaherty's, and he's far more well-known for his changeup than for his curve. This is because his changeup is good, and his curve really sucks. It hasn't made the progress that a lot of people hoped it would, and right now it's nowhere close to being Major League-caliber.

That's not the best recipe for a potential Sherrill successor. It's not unheard of for a fastball/changeup guy to make it as a lefty specialist - it's worked kind of all right for Aaron Fultz and Dennys Reyes - but it's a lot more difficult, and the odds of dominating are slim. The reason you don't see many lefty relievers lacking a quality breaking ball is that it's almost impossible to make it without one. And right now, Cesar Jimenez is without one.

If Jimenez ever makes it into a Major League bullpen, it should be as a sponge for low-leverage middle innings, a guy who can face two or three or ten hitters of all shapes and sizes without embarrassing himself. Unless he proves to be an exception to the rule - and there's no evidence of this - then that's the job for which he's most cut out.

And O'Flaherty, he's ready to help out against tough lefties right now. He's not George Sherrill, but few people are, and his slider should be good enough to keep him from being a liability. While his change may not be good enough to keep righties quiet, given Sherrill's typical usage pattern, that shouldn't be much of an issue.

In my book, this is no contest. Hopefully the team is just using Jimenez as motivation for O'Flaherty to put forth a stronger effort, similar to how it used Fernando Vina two years ago, because that's the only way this really makes sense. So here's to a full season of delicious potatoes. With none of them mashed.