Do the Yankees need to trade for another bullpen arm?

The Yankee bullpen was a big strength for the team in 2009. No reliever who appeared in 40 or more game posted an ERA over 4.50. It has certainly been a different story in '10. Excluding Mariano Rivera, who has a miniscule 1.05 ERA, no Yankee reliever who has appeared in 13 or more games has posted an ERA under 4.08. Joba Chamberlain, David Robertson, and Chan Ho Park have posted 5.79, 5.48, and 6.18 ERA's respectively. What's going on with the Yankee bullpen? Let's go through the stats of each current member of the bullpen individually.

Rivera has gone 2-1 with a 1.05 ERA, 20 saves, and 33 K's in 34 relief appearances and 34.1 IP. He has given up just 16 hits on the year for a tiny 4.2 H/9 ratio. That's less than 1 hit every 2 innings! He has walked just 6 batters on the year, or 1.6 per 9 innings. He has struck out 8.7 batters per 9 inning. Also, Rivera has given up just 1 homer all year, the grand slam to Kubel. He has been amazing and nearly untouchable.

Joba has gone 1-4 with a 5.79 ERA, 18 holds, 2 saves, and 40 K's in 39 relief appearances and 37.1 IP. He has a great 9.6 K/9 and a decent 3.4 BB/9, but what's been bad for Joba has been the amount of hits he has given up. He has given up 42 hits, more than a hit per inning, for a 10.1 H/9 ratio. It's all about the amount of hits given up. He's has struck out more than enough batters, and walked few enough batters, but he's just given up too many hits. More problems with Joba include a .293 BA against him by righties compared to a .269 BA by lefties, and allowing batters to hit .348 against him with runners in scoring position. But, all hope is not lost for Joba. He has been incredibly unlucky. Batters are hitting a ridiculous .370 on balls in play against him. That's .70 over the MLB average! Batters are even hitting .333 against him on ground balls! Hopefully that will turn around soon and Joba will end the year with a repectable 4.00 ERA. But, can Joe Girardi wait for Joba's luck to change? Joba has a critical role in the bridge to Rivera as the setup man. Should the Yankees acquire another reliever to be setup man? I think yes. The Yankees should acquire a player such as Octavio Dotel that can step into the setup role so Joba can straighten himself out in situation with less pressure. Then, when Joba does straighten himself out, he can move back into the setup role, while that acquired reliever remains an important part of the bullpen assuming he does well. Joba hasn't been good so far, but he's had bad luck on balls in play and his luck will eventually turn around.

Robertson has gone 1-3 with a 5.46 ERA, 6 holds, and 32 K's in 31 relief appearances and 29.2 IP. He has posted a great 9.7 K/9, but a below-average 5.2 BB/9. Also, just like Joba, he has given up 36 hits for a bad 10.9 H/9. Robertson has just allowed too many base runners. He has allowed nearly 2 base runners per inning. He has also allowed a .316 BAA against righties and a .283 BAA against lefties. Robertson has been even more unlucky than Joba, allowing an improbable .398 BA on balls in play. He has allowed a crazy .343 BAA on ground balls, a .357 BAA on fly balls, and even a .500 BA on bunts But, despite the extra base runners, Robertson has a better ERA than Joba. He has allowed a better .303 BA with runners in scoring position. I think Robertson will also straighten things out by season's end. With better luck, he could have had a 3.50 ERA or better. An acquired reliever would allow Robertson to appear in some situations with less pressure. Just like Joba, Robertson has had terrible luck that has led to his bad performance, and his luck will eventually turn around.

Chan Ho Park has gone 1-1 with a 6.18 ERA, a terrible 0 holds, and 22 K's in 21 relief appearances and 27.2 IP. He struck out a decent 7.2 batters per 9 innings, and posted a great 2.3 BB/9 ratio. But, the continued theme is too many hits allowed per9 innings. Park has allowed a completely terrible 11.1 H/9 ratio. Park has been a bit unlucky, allowing a .326 BAA on balls in play, but the real reason he has a 6.18 ERA is because he has allowed 2.0 homers per 9 innings. That's more homers than Rivera, Chamberlain, and Robertson have allowed per 9 innings COMBINED. He has just been terrible. I don't think there's anything the Yankees can do with him. They should designate him for assigment.

Damaso Marte has gone 0-0 with a 4.08 ERA, 9 holds, and 12 K's in 30 relief appearances and 17.2 IP. He has struck out 6.1 batters per 9 innings, but walked a bad 5.6 per 9 innings. He has allowed only 5.1 hits per 9 innings, so he has been hard to hit. Unlike Joba, Robertson, and Park, he has been incredibly lucky. Batters have hit just .161 against him on balls in play. He has a 4.08 ERA because of his 5.6 BB/9 and because he has allowed exactly 1 homer per 9 innings. He has been pretty good.

With Alfredo Aceves and Sergio Mitre hurt, and Boone Logan and others sent down to the minors, the only other active Yankee reliever is Dustin Moseley. He has gone 0-0 with a 3.00 ERA in 2 games. I hope he can keep that kind of ERA going.

So, the Yankees do need another reliever. Joba and Robertson are still waiting for their luck to change, and Park is just a complete disaster. Another reliever could help every reliever in the bullpen be comfortable, and play well.