Jonathan Pettibone is a new, shiny thing. His ERA is 3.41, and he is 3 - 0, so of course, the casual fans I know are starting to get excited despite my admonitions to avoid falling in love. He's 22, throws right-handed, and a young, successful Phillie is so...so...so 2005. We want to believe.
My job is to disabuse you of any naivete. This is 2013, so we don't hope around here, right? Well, not exactly (see #9). Still, we need to be realistic.
The obvious thing from his Fangraphs non-splits line is that his strand rate is outrageously high right now. In other words, he is allowing baserunners, but he is smartly refusing to allow them to score. That's a great plan, but it does not last.
Nobody strands 84% of runners consistently. A few pitchers are close, but none of the 85 qualified starting pitchers hit 84% for a full year in 2012. Here is the Fangraphs LOB% leader board for starting pitchers for 2012, if you don't believe me. Jeremy Hellickson is some kind of Matt Cain-ian wizard, and Pettibone is no Chris Sale or David Price, who can dial up strikeouts as-needed. Unless Pettibone is a true outlier, we should expect to see Pettibone's strand rate decrease toward the 75% range that most MLB starting pitchers hover around.
Pettibone does not strike out many batters. He is walking too many-ish, given his low rate of strikeouts. Whiffing 5.64 per nine innings and walking 2.42 per nine innings just won't do it. The walk rate is not bad, but the K rate is just too low. His groundball rate is solid at about 45%, but he's no Trevor Cahill or Tim Hudson. Here is the leaderboard on groundballs for 2012 starting pitchers.
All of this is essentially provided to us in the aggregate in Pettibone's FIP at Fangraphs (see the non-splits link at the top of this article) which tells us he has a 4.77 FIP after the start against the Indians on May 14, 2013. His xFIP is close to that (4.62) telling us that his HR rate on flyballs is not really out of line.
So the Phillies have a 4.77 FIP player filling the role of fourth starter right now behind Hamels, Lee, and Kendrick. That means the Phillies will be expecting their 22 year-old starter to be among the 91st - 120th best starters in Major League Baseball.
Here is a great article on "fifth starters" in MLB. The same holds true for "fourth starters" to a large degree. In a nutshell, if you do not RTFA, very few teams in MLB have five starters who rack up 25 or more starts per year. At the back of the rotation, it gets really hairy at times, and even the Phillies, with a fairly sound rotation during even 2012, had 9 pitchers start games for them. The Mets used 13 starting pitchers and had only 2 with more than 21 starts. The Royals used 13 starters with just three starting at least 25 games.
The last two starters in the rotation are not really filled by one player for each slot. Nor are the roles really solid. The fourth and fifth starters, at least for many teams, are generally a conglomeration of cast-offs, has-beens, never-weres, or maybe young pitchers getting a trial. Remember the days of Durbin? J.D. Durbin? Yeah...it wasn't always aces. For lots of teams, that is the reality of the fifth starter role, or even the fourth starter role.
Again, with 85 qualifiers in MLB in 2012, here is the Fangraphs "reverse leaderboard" for FIP for starting pitchers. The "winner" is Ervin Santana at 5.63. Distributing the pitchers evenly among the thirty MLB teams, you will see that these are technically third starters, and some of them are much worse than Pettibone. While ERAs have fallen since this article, it is a point well taken. Even for 2013's starters, 108 of whom qualify for this list, Pettibone is performing better than many, including some pretty big names.
The Phillies do not have a "Baby Ace" in Pettibone, but it appears that they have a workable 4th starter. He is the 10th youngest player in the National League right now. His minor league FIP suggests that he has been able to perform well against similarly-aged competition, so as he matures it is not unreasonable to wishcast a little and hope that he can be more than a 4th starter as he ages. Hell, even Kyle Kendrick blossomed.
And oddly, it seems that the Phillies have a good sense about which young pitchers they should promote, from Kendrick to Happ to Worley. Every couple of years, they get mileage out of a guy for whom the results seem a little surprising. As much as we complain about how the team is run sometimes, they seem to have a handle on the young starting pitchers in the system.
So, is Jon Pettibone going to save 2013? Probably not. A fourth starter usually isn't a savior. But he is a necessary part of retooling the Phillies, and it is good to see a young player having success, though we should expect to see him struggle some.
The early returns are partly luck based, but there is a young player here whose pitching inputs would be useful even with normalized outcomes. He is pitching over his head, but he looks like he belongs, and during a game when Domonic Brown homered and Freddy Galvis made plays and Justin De Fratus helped the Phillies out of a jam in a high-leverage situation late in the game, it was not too hard to squint a little and imagine that the future is coming.