In the comments about last night's 14 inning Phillies win, awh posted some interesting numbers about the Phillies bullpen. Here's one: over the last 30 days, they are number 1 in the National League and number 2 in MLB in fWAR. This covers May 28 through June 26. During that period, the team is 14 - 15. Being 28th in MLB in position player fWAR has some impact on that, of course. So does being 24th in MLB in starting pitching fWAR.
But let us not complain. Let us celebrate!
No, I did not predict this all along, either.
How did this happen? Let's look at the components of pitcher success:
Walk Rate: Phillies relievers are walking 3.47 batters per 9 innings. That is 19th out of 30 teams. They still walk too many batters. This is not making them the best bullpen in the NL or the second-best in MLB. With the funky nature of bullpen scenarios, though, walks over a 30 day sample can be a tricky metric because of intentional walks.
Over 85.2 innings, the team has walked 33 batters and given 7 intentional bases on balls. That is tied for second with four other teams in MLB over that period. Backing out intentional walks gives a walk rate of 2.73 per nine innings. Thirteen teams have 2 or fewer intentional walks over the period, so the Phillies inflate their walk rate based on the situation. Given that these walks are the call of the manager, they do not reflect the accuracy and control of the players.
Strikeout Rate: The Phillies are 4th in MLB and 2nd in the NL at 10.19 strikeouts per 9 innings over the sample period. Justin De Fratus, Jake Diekman, Kenny Giles, and Antonio Bastardo are big reasons why this is high right now. This is objectively good no matter how you slice it. This is what you get from the stuff that Diekman and Giles have.
The Giancarlo Stanton and Marcell Ozuna at bats against Giles in the 14 inning game give me pause about Giles, though. He needs his slider to make the fastball work, even in the high 90's. Diekman's motion and movement are fantastic, along with his velocity. Giles has a more conventional delivery and his fastballs look less wicked. It looked like Stanton was able to deal with it, as he kept fouling it back. He's Giancarlo Stanton, though. It bears watching as Giles gets more innings, though.
Bastardo's utter transformation (not walking anyone and striking out people at a super-high rate) surprises me. We see him be effective for long stretches, but then he lays an egg. It's the nature of relief pitching to an extent, but I would be shocked to see Bastardo continue to avoid walks this way going forward. He's coming back to earth sooner or later.
De Fratus seems to finally be putting it together. I've had a good feeling about him for a long time. That 2,500 word bullpen screed basically ignored Diekman, though. You win some, and you lose some. De Fratus' slider, and his ability to throw it for strikes, has been the talk of the broadcasts. I think De Fratus is just being 27 years old (almost) and doing what he did against people in the minors. He may have finally leveled up from AAA.
BABIP: Well, it can't all be good news, can it? The .237 BABIP is the 2nd lowest in baseball, and far from the mean at about .285. Yeah, there's that. Those two awesome Cody Asche stops in extra innings? Yup. Some of that stuff is going to start getting through again. Particular beneficiaries have been Giles and Bastardo. Diekman and De Fratus have not been BABIP-fueled. To the contrary, they seem to have been bitten by the BABIP bug more often than not. That's actually a good thing.
Home Run Rate: The home runs on fly balls percentage is 6.8%, which is really good. There are 21 teams doing worse. The mean looks to be a little under 9%. They are a little better than that, but not outrageously so, like the Nationals at 1.4%.
Ground Ball Percentage: The Phillies are a mixed bag here. Some are decent ground ball pitchers, such as Diekman and De Fratus. Others, like Bastardo and Papelbon, are not. Still here is the MLB list The Phillies are nearly dead last at 38.2%. Another high strikeout team, the Reds, is below them. Average is about 47%. Despite history, the only Phillies among the main six current bullpen options of Bastardo, Diekman, De Fratus, Papelbon, Giles, and Hollands with high groundball rates are the latter two: Giles and Hollands. I expect the groundball rate will increase. It seems a little out of line right now.
ERA/FIP/xFIP: As you may suspect, the Phillies have an ERA that is outperforming their FIP and xFIP. The ERA is 1.79 over the period. FIP is 3.04. xFIP is 3.46. The FIP vs. ERA difference is 1.25, which is far and away the largest gap in baseball right now, in terms of overperformance or underperformance. The xFIP of 3.46 is 10th in all of baseball, and 4th in the NL, so it is objectively good, but it suggests that the bullpen is not as elite as recent performance may make us think.
Going forward, we can expect the bullpen to perform at a lower level. Enjoy it while it lasts. Still, this is not a bullpen that is likely to pumpkinize. These players have been objectively good for a long stretch. While they have parleyed good performance into elite results with some luck, they are not a tire fire, or even close to being one.
The core of the unit is very young and inexpensive, as well, with balance in handedness and in styles. In a team that has lots of warts and weaknesses, the bullpen, at last, may not be among them.