The Phillies and their up-and-down bullpen

The nature of bullpens is that they are unpredictable. However, the Phillies are stretching that axiom to its outer limits.

Last night in Anaheim, the bullpen blew a 2-0 lead handed to them by recently-acquired journeyman Jerome Williams and gave up seven runs, six earned, in the sixth inning of the Phils' 7-2 loss to the Angels.

Antonio Bastardo was the main culprit this time around. He gave up four earned runs on four hits and a walk, and recorded just one out, before finally being relieved by Jake Diekman. Mario Hollands and Cesar Jimenez cleaned up the mess with a scoreless final two innings, but by then the damage was done.

The Phils' bullpen is filled with youth, and that youth has resulted in some maddening inconsistency. The relievers' 3.97 ERA and strand rate of 70.4% are both 2nd-worst in the National League, and their xFIP of 3.71 and 3.73 walks per nine are 4th-worst.

However, their fWAR of 2.3 is tied for 6th-best in the NL, and their K/9 rate of 9.39 is 4th-best, which are both solid numbers. Unfortunately, they haven't been as successful getting batters to hit the ball on the ground, with an NL-worst 41.3% ground-ball rate and a league-high 38.8% fly-ball rate.

Strikeouts are good. A bullpen full of arms that misses a lot of bats is more likely to keep inherited runners from scoring than arms that rely on batters to make contact. But a lack of ground balls means a lack of double plays, and an elevated fly ball rate means more home runs than normal.

However, the Phils do have at least two powerful young arms they feel good about for the future.

Among relievers with at least 20 innings pitched this year, Ken Giles is 4th in the National League with 13.50 K/9 and Jake Diekman is right behind him in 5th, at 12.74 K/9. Giles has already generated 0.8 fWAR in just 23 innings pitched, which is pretty insane. Bastardo is 18th in the NL at 11.22 K/9, but has also walked 5.08 batters per nine, which is 10th-highest among NL pitchers with at least 20 innings pitched.

What's crazy is how unpredictable the bullpen has been. Per Meghan Montemurro of Delaware Online, before Tuesday night, the bullpen posted a 0.90 ERA over its last 27.2 innings, and since August 5th, their bullpen ERA of 0.36 was 2nd in all of baseball. During that time, they struck out 30 batters and gave up just 13 hits, good for a batting average against of .140.

Then, last night happened.

And if you look at their stats month-by-month and by first and second half, you see a schizophrenic pattern of behavior.

The addition of Giles to the bullpen has been a huge help, posting a 1.50 ERA in 24 innings, with 36 strikeouts and six walks. Justin De Fratus' 2.90 ERA in 40.1 innings has been solid as well, and Jonathan Papelbon's 1.64 ERA and 27 saves continues to defy his 3.78 xFIP.

Jake Diekman has been the victim of some bad luck this year, with a .347 BABIP and xFIP of 2.61. And before you jump on the whole "Diekman is a LOOGY" bandwagon, consider he has given up just a .241 batting average and .388 slugging percentage to right-handed hitters this year. He can get them out.

Mario Hollands, the Phils' 3rd left-hander in the bullpen, has shown flashes at times this year, but his 4.03 ERA, 3.95 xFIP and 6.85 K/9, as well as his lefty-righty splits, indicate he should be the LOOGY in the 'pen. Left-handers are hitting .211/.282/.271 against him this year, with right-handers batting .263/.349/.402.

KEEP MARIO AWAY FROM RIGHT-HANDERS, RYNE!

With so many kids gaining experience in the 'pen, though, nights like Tuesday night are going to happen. Overall, I think it's fair to say the 'pen has largely been a positive for the Phillies this year, and should be one of the team's strengths heading into 2015.