What Bailey brings, and what's next

Breaking down the implications of and the numbers behind Wednesday's trade, as the Boston Red Sox acquired Andrew Bailey and Ryan Sweeney from the Oakland A's for Josh Reddick and two minor leaguers.

Getting to know Bailey

Bailey joins Kaz Sasaki and Billy Koch as the only pitchers with at least 24 saves in each of their first three seasons. Dick Radatz would retroactively make the list, but saves were not yet an official statistic.

Perhaps a more apt list also incorporates Bailey's ERA. He's one of four players with 70 saves and an ERA below 2.10 over his first three seasons. The others? Jonathan Papelbon, Takashi Saito and Joakim Soria.

Bailey's start puts him in rare company, but Baseball-Reference.com provides perhaps the best comparison. The most similar player to Bailey at this stage was Troy Percival. Both were 26 in their first season and dominated right away. After three seasons, Percival had 66 saves and a 2.48 ERA. Bailey has 75 saves and a 2.07 ERA.

Essentially half of Bailey's appearances have come in pitcher-friendly Oakland, but that's not cause for concern. His 1.96 career ERA on the road is actually lower than the 2.17 posted in Oakland.

Bailey is a rare reliever who is dominant against batters on both sides of the plate. Righties are hitting .194 against him, while lefties hit .182. Only four other pitchers can boast a sub-.200 opponent batting average against both sides: Carlos Marmol, Daniel Bard, Neftali Feliz and Mike Adams.

Bailey and his cutter

How did Bailey go from a 4.32 ERA in Double-A in 2008 to Rookie of the Year in 2009?

It's amazing what one pitch can do.

Bailey learned to throw the cutter during the 2008 season under the tutelage of A's roving pitching coordinator Gil Patterson, a renowned cutter guru.

Averaging almost 89 mph, the cutter provides a change of pace from Bailey's 94 mph fastball. It immediately became a key part of his repertoire. Opponents hit .139 on at-bats ending in the cutter in 2009 and .186 in 2010.

The cutter may also help explain why Bailey's ERA jumped to 3.24 last season. Opponents hit .280 on his cutter.

One reason was difficulty locating the pitch. In his first two seasons, Bailey threw 55 percent of his cutters in the strike zone. Last season, that fell to 45 percent.

"I'm not going to blow it by you at 98, 99. I'm not that type of guy,'' Bailey told reporters on a conference call Wednesday. "I usually sit in the low 90s and rely on control and getting ahead of guys.

"There's a motto I live by: 'Strike one is the best pitch in baseball.' If you stick with that, you'll be fine."

Sweeney's role

Ryan Sweeney does nothing to address the key offseason goal: Acquiring a right-handed hitting right fielder to add balance to a lefty-heavy lineup. Not only does Sweeney hit lefty, he's proven to be terrible against southpaws, with a .595 career OPS.

As a fourth outfielder and potential platoon partner in right, Sweeney makes far more sense, especially with the news that outfielder Ryan Kalish had surgery to repair a labrum tear in his left shoulder in November and will not be ready for Opening Day.

The remaining free-agent market leaves few enticing platoon partners, most notably Andruw Jones, Ryan Ludwick and Cody Ross.

GM Ben Cherington provided a window into what the Red Sox see in Sweeney.

"We also really like his offensive approach to Fenway," he said. "He's got an opposite field approach."

When hitting to the opposite field over the past three seasons, Sweeney is hitting .377. Compare that to .279 when pulling the ball.

When hitting the other way, Sweeney does a far better job of lifting the ball. Since 2009, 72.4 percent of his opposite field hits have been fly balls or line drives. Compare that to just 32.4 percent when pulling the ball.

No one is comparing him to Adrian Gonzalez, but the essential logic is the same. The Red Sox have identified a player who should benefit from playing at Fenway Park, and essentially the Green Monster.

What's next?

Who is the player most impacted by the acquisition of Bailey? It has to be Ryan Madson, who sees yet another potential suitor go elsewhere.

On the Red Sox, the player affected the most may actually be Alfredo Aceves.

Bailey made just $465,000 last season, though he's due for a raise in arbitration. That's a significant savings from Papelbon, Madson or the other potential free-agent options.

So how does that impact Aceves?

With a closer locked up and no big-name right fielders on the horizon, the Red Sox can dive into the starting pitcher market. Roy Oswalt, Hiroki Kuroda, Joe Saunders and Edwin Jackson all remain available.

That would seemingly push Aceves back into the bullpen, a place where he's likely better suited.

Though Aceves posted a 2.61 ERA last season, his xFIP (expected fielding independent pitching) was 4.77. A similar huge discrepancy helped predict Clay Buchholz's decreased production prior to his injury. A move to the rotation likely would only hurt Aceves' already high walk rate.

The Bailey acquisition provides Boston with the payroll flexibility to return Aceves to the role in which he proved valuable in 2011.

Jeremy Lundblad is a senior researcher with ESPN Stats & Information. He provides statistical analysis for ESPNBoston.com.