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Ubaldo Jimenez is a very talented pitcher.  After all, the vast majority of the pitchers on the planet cannot throw 100 mph while mixing in a nasty changeup, curveball, and slider.  However, the Ubaldo Jimenez who has 12 wins a month before the All-Star break and carries a microscopic 1.16 ERA into his start for the Rockies against the Twins at Target Field this afternoon has not been very different than the regular front of the rotation flamethrower that posted a 3.47 ERA while playing half his games in Coors Field last year.

Looking at SIERA is an excellent starting point to get a sense of how well someone is truly pitching.  No metric can be the beginning and ending statement in a player’s performance, but SIERA does a very good job at determining how well pitchers are doing—particularly those who help themselves with good ground-ball rates, like Jimenez. Last year, Jimenez posted a 3.60 SIERA, good for 20thamong major-league starters. That's fantastic. The majority of pitchers with 3.60 ERAs in any given year are lucky and see their ERAs go up the season, while pitchers with 3.60 SIERAs tend to have ERAs that stay low.  In Jimenez’s case, his ERA has plummeted.  However, his SIERA has improved to just 16thamong major league starters at 3.43.  That is a slight improvement but it also indicates that Jimenez has been a very lucky pitcher.

Sabermetrics has long backed off the claim that pitchers do not control their batting average on balls in play (BABIP), but what we have learned is that pitchers do not have very much control over it. Jimenez has a .235 BABIP, compared to the major-league average of .298.  There are great pitchers that are capable of dropping their BABIPs to .280 on a consistent basis, but none who can mentally will weakly hit balls from becoming bloop singles or 20-hop singles. And it is not possible for a pitcher to allow only hits on 23.5 percent of balls in play over a prolonged period of time. The pitchers that tend to hold their BABIPs down also do not play their games at Coors Field.  Even with Colorado’s terrific defense, the rest of the Rockies pitchers have only a .292 BABIP. Flamethrowers can certainly hold BABIP down a few extra points, but Jimenez has been fortunate to come in so far below his similar BABIP-preventing fastball wizards.

Breaking down Jimenez's BABIP, we see that his line-drive rate is 17 percent, just below the 18 percent number he had in both 2007 and 2008. Pitchers have extremely little ability to control their line-drive rate, even if they do have a little bit more control over the actual BABIP on line drives (though not much). My theory is that hitters slow down their swings against pitchers like Jimenez. Thus, they square the ball up on the bat as often, but do not hit it as far. Jimenez's BABIP on line drives is .600, well below the major-league average of .722.  This is just not sustainable, especially in Coors Field where line drives fall in more than in the average park.

Pitchers do not have a large amount of control over the amount of ground balls that reach the outfield. The major league average is about 17 percent, but the Rockies’ defense is pretty good, which explains why 15 percent of Jimenez’s ground balls reached the outfield in 2009. However, this year only 11 percent of his ground balls have trickled through. That is not sustainable and also helps explains why his BABIP is likely to rise.

In fact, even though Jimenez has given up fewer hits on batted balls in play, his rate of doubles and triples has increase from 5.8 percent last year to 7.8 percent this season. However, his rate of singles on balls in play has fallen from 22 percent to 16 percent. The difference is a lack of weakly hit balls finding space to cause problems.

Even more fortunately, Jimenez has been able to strand over 90 percent of runners due to a .186 BABIP with men on base. There is no way that Jimenez can continue that performance. He has made some excellent pitches, but major league hitters are too good to let that kind of hit prevention to persist.

Jimenez’s BABIP has not only been the source of good luck. He has allowed only three home runs so far this year. The problem is that pitchers that keep home run rates down also keep the ball out of the outfield air, and while Jimenez is good at generating ground balls, he still has allowed 52 fly balls to reach the outfield, which means that he should have closer to seven home runs surrendered—his rate of home runs per outfield fly ball has dropped from 10.4 percent last season to 5.8 percent this year.  Pitchers that prevent home runs on fly balls (and not even Mariano Rivera can reliably get rates this low) generally also tend to cause pop-ups, but Jimenez’s pop-up rate has actually decreased from 6.4 percent last season to 5.1 percent this year. Instead of letting fewer balls reach the outfield in the air, Jimenez has seen an increase from 34 to 36 percent of his batted balls reach the outfield in the air. Those balls have just concentrated in the middle of the outfield, without flying over the fence. Chances are that some of those fly balls will find themselves on the other side of the wall soon enough.

Jimenez has not even missed more bats this year. His rate of swinging strikes has fallen from 9.6 percent in 2009 to 9.0 percent in 2010. He has made up for that by getting hitters to chase more pitches out of the zone—up from 24 percent last year to 27 percent this season. Meanwhile, he has also gotten them to look at more pitches in the strike zone (up from 35 percent last season to 41 percent this season).  With a similar number of pitches in the zone but fewer swings at the pitches that are easier to hit, it is no wonder that Jimenez has struck out more hitters as a result—up from 22 percent last year to 24 percent this season, while his walk rate has stayed roughly constant, going from 9.3 percent to 9.6 percent.

It is tough to write an article calling for the fall of Jimenez, because the fall just is not going to be that bad. The 26-year-old Dominican is one of the 20 best pitchers in the major leagues, and could get better given his youth. There are very few pitchers who can strike batters out so easily, all while generating 55-56 percent ground balls, a feat Jimenez has accomplished three years in a row. Even if his 3.43 SIERA matches his ERA the rest of the way, he will still finish with an ERA around 2.60, and he’s a good bet to get 20 wins with 12 already in the bank. I think he wins the National League Cy Young award this season and is good enough to do it more than once in his career. However, most pitchers who win the Cy Young have some luck come their way, and Jimenez is no exception.  In fact, he’s been fantastically lucky which has finally drawn plenty of attention to the fact that he is a great pitcher. That said, he is just not the best, at least not yet.