Roberto Hernandez Heads to the Land of Cheesesteak

No, not the Roberto Hernandez who saved 326 games and spent his career in the bullpen, silly. It’s the Roberto Hernandez who became the artist formerly known as Fausto Carmona of course! After a disappointing season with the Rays that saw him post a 4.89 ERA and eventually get banished from the starting rotation, Hernandez signed a one-year deal with the Phillies yesterday. Twice Hernandez has earned positive value in fantasy leagues, while he has torpedoed the ratios of many a team in all other seasons. Now he moves into the National League, where pitchers typically see a bump in value.

But before diving into the ballpark and league switches, let’s discuss Hernandez’s skill set. Throughout his career, he has proven to absolutely hate worms. He owns a career GB% of nearly 58% and has never posted a mark below 50%. That’s a great skill to have, but it also requires a good infield defense, otherwise an inflated BABIP is likely. This is especially true since ground balls go for hits more often than fly balls, so a porous infield defense is only going to exacerbate the problem.

This year, the Rays ranked 7th in baseball in UZR/150 and 4th in the American League. The Phillies, on the other hand, ranked 27th in baseball and next to last in the National League with a highly negative mark. Defenses do change from year to year, sometimes significantly so, but the numbers suggest that he is likely to receive worse defensive support next season.

Aside from his disastrous 2008 and 2009 seasons, Hernandez’s control has been good and his F-Strike% has increased for three straight seasons. Most interesting though is that his strikeout percentage hit a career high, though it still remained below the league average, as did his SwStk%. He threw his change-up much more frequently this year, which makes sense since it has been his best pitch, generating a SwStk% of 14.8% over his career. The increased usage of that pitch likely led to the strikeout rate surge.

But while Hernandez posted a respectable 3.66 SIERA, he was killed by the home run ball, as evidenced by his 20.9% HR/FB ratio. While he has been prone to home run problems in the past, there’s no way a rate that high is going to be repeated. Over his career, he has underperformed his SIERA and he’s pitched over 1,000 innings already. Since he’s had problems with both the long ball and in stranding runners, it might just be an inherent lack of skill in those areas rather than bad luck.

Now let’s get to the park factors for both Tropicana Field and Citizens Bank Park:

As you would have suspected, Tropicana Field suppresses overall offense, though Citizens Bank is close to neutral, despite boosting home run totals. Since Hernandez is an extreme ground ball pitcher, he wouldn’t be as affected by a move into a better home run park. But since he’s had a history of posting inflated HR/FB ratios, then he should probably be treated more like a pitcher with a neutral batted ball profile. Overall, the park switch is a negative.

Just about the only reason to be optimistic is the move to the National League. Let’s check out the average starting pitcher’s relevant skills in each league:

We have grown accustomed to expecting a strikeout rate surge when a pitcher heads to the National League. But surprisingly, the two leagues shared nearly identical rates this year. Of course, the pitchers in each league are different and so we aren’t exactly comparing apples to apples. Perhaps the National League just doesn’t have the strikeout artists the American League has. So even though the data suggests the league average is the same, you still have to assume that all else being equal, Hernandez should enjoy a strikeout rate jump. Walk rates have always been about the same, so there should be limited movement there from the league switch.

Despite similar skills from each leagues’ pitchers, the National League held a nearly 0.30 run advantage over the American League. The reason could be explained quite easily by looking at two of the three luck metrics. National League pitchers allowed a lower BABIP and HR/FB ratio, both of which are probably due to pitchers batting, a group that is obviously going to reduce the averages of both metrics.

So the ballpark and team switch are both negatives, as the Phillies offense scored just the 13th most runs in the National League, while the Rays scored the 9th most. It’s not a big difference, but the offensive support would likely be better in Tampa Bay. The defense is probably going to be worse as well. Fortunately, he should be able to count on a strikeout rate spike and some better luck preventing hits on balls in play and keeping fly balls in the park.

I probably wouldn’t bother with him in 12 team mixed leagues, but I think he makes for a decent gamble in an NL-Only league assuming you can acquire him at a cheap price.