You may not have noticed, but last night's game featured another Major League debut, with the 21 year old southpaw getting called on to pitch the ninth inning of a 6-2 game. And Jimenez, the latest in a seemingly endless stream of heavyset pitchers we get from Tacoma, did about as well as anyone could've hoped, recording a flyout, a strikeout, and a blooper that Ichiro was able to snag with a three-quarters dive attempt. It wasn't anything flashy, but pitching a 1-2-3 inning in the first ML game of his career is something Jimenez will be talking about for the rest of his life.
Here's what you need to know about the guy - after spending the last two years in relief, Jimenez moved back to starting this year and allowed 59 runs in 117.2 innings between AA/AAA. He did come within three outs of a no-hitter, and he had a spectacular June ERA, but his undoing proved to be a miserable combined 1.20 K/BB. It's tough to succeed for any length of time when you miss the zone as often as you miss the bat, so much of Jimenez's season was more a learning experience than anything else.
That said, I don't want to talk about his performance so much as I want to talk about his repertoire, and what it means for him going forward. Despite the relatively recent addition of a curveball (which he used to strike out Russ Adams looking), Jimenez has long been viewed as a two-pitch pitcher, attacking with an 87-90mph fastball and a changeup that many think is the best in the system. That changeup is his out pitch, and it's what allowed him to build a decent track record for someone his age - minor league hitters, particularly the ones populating lower levels, just aren't real good at hitting offspeed pitches, so Jimenez was able to get by without deviating too much from his gameplan.
Here's the thing about changeups, though: they're thrown primarily to opposite-handed hitters. This is true across the board at pretty much any professional level. RHP's throw breaking balls to RHB's and changeups to LHB's; LHP's throw breaking balls to LHB's and changeups to RHB's. And there's a good reason for this to be the case - it's much harder to make solid contact on a pitch that breaks away than on a pitch that breaks in. When a pitch breaks in the hitter's direction, it speeds up his bat and allows him to get out in front of the ball, often resulting in a line drive or a well-hit fly. When a pitch breaks away from the hitter, he'll either have to slow down his swing to hit it the other way, or get it off the end of the bat/miss it entirely, producing much more desirable results (for the pitcher). It really is as simple as that.
(Changeups naturally have a little screwball motion, which is why they're thrown to opposite-handed hitters - they tail down and away, like reverse curveballs. Maybe I should have mentioned this earlier.)
So with all this in mind, let's take two lefty pitchers: George Sherrill and Cesar Jimenez. Sherrill has a fastball, a good breaking ball, and an unreliable changeup. Jimenez has a fastball, a good changeup, and an unreliable breaking ball. What do you suppose they're each going to give to you?
A southpaw with Sherrill's profile is going to perform better against lefties (.595 OPS, 7.00 K/BB) than against righties (.798 OPS, 0.75 K/BB). A southpaw with Jimenez's profile is going to perform better against righties (.740 OPS, 1.36 K/BB) than against lefties (.771 OPS, 0.81 K/BB). It's right there in the numbers. Sherrill has the repertoire of a LOOGY, while Jimenez has the repertoire of someone with a borderline reverse platoon split (the difference isn't as wide as Sherrill's because you still have to take into account the hitters' platoon splits, which are almost never reversed). You can overcome the changeup/breaking ball stuff if you have a good enough heater (which is why the Mariners hung on to Matt Thornton for so long), but neither Sherrill nor Jimenez are particularly overpowering, so their success depends on their secondary pitches.
So what does this tell us about Jimenez's future? It suggests that, unless he learns how to throw a better and more consistent breaking ball, he's never going to pitch as well against left-handed hitters as you'd like to see from a southpaw. The changeup is a neat tool against righties, but Jimenez's inability to throw strikes or miss bats against lefties spoils his long-term LOOGY potential, which is generally the easiest way for a southpaw to make a living throwing a ball. If he wants to force his way into a more permanent ML job, he's going to have to make a breakthrough. He clearly isn't a good starter right now, even at the AAA level, and many managers are reluctant to trust a left-handed middle reliever, so Jimenez absolutely needs to improve his curveball if he wants to stick. There's just no other way around it.
The good news for Jimenez is that he's still plenty young, and has more than enough time to work on his third pitch. It's also worth noting that, if nothing else, he's demonstrated an ability to keep left-handed hitters out of the air, as evidenced by his ridiculous 72.3% groundball rate against LHB's. He doesn't throw them many strikes, but at least when he does, they don't travel very far.
The bad news is that, in the history of AAA baseball, there are countless arms who ended up one pitch short of breaking into the Majors. If learning a new pitch were easy, everyone would do it, and league ERA's would be down in the 2's. Like mechanical adjustments, repertoire additions take a lot of work and a lot of concentration, and more often than not they fail to achieve what they set out to accomplish.
The odds are stacked against Cesar Jimenez. Even when you take into account his age, his control sucks and his arsenal is too limited, and these are pretty difficult obstacles to overcome. That said, though, his ML-caliber changeup makes him worth keeping an eye on, because when young guys with that kind of weapon make gains, they tend to be significant. Jimenez isn't in anyone's 2007 plans as far as the big league roster is concerned, but if he's able to bear down and spend the next calendar year working hard on his curveball, we could be talking about him a lot in 2008. Keep him in the back of your mind.