(A five-part series about the players most integral to the success the Red Sox enjoyed this season. Previously appearing on the countdown: Closer Jonathan Papelbon at No. 5 and starting pitcher Josh Beckett at No. 4.)
Two other players -- it shouldn't be hard to guess their identities -- could be considered more valuable to the Red Sox this season than Jason Bay. No player, though, personnified the ups and downs of the Red Sox season more than the slugging left fielder.
From Opening Day until June 23, a span during which Bay OPS'ed .989 and inspired "Sign Jason Bay" chants all over New England, the Red Sox went 43-27 (.614) and surged out to a five-game lead in the American League East. Over the next six weeks, though, Bay hit .177 and OPS'ed .614 as the Red Sox tumbled 6 1/2 games behind the Yankees.
But from Aug. 10 until the end of the season, Bay hit .301 and OPS'ed 1.026 as the Red Sox kept pace with the Yankees and locked up the American League's wild card.
The Red Sox knew they'd be getting a streaky hitter when they acquired Bay. Check out some of his Mays and Junes over the years:
May 2006: 1.090 OPS
June 2006: .776 OPS
May 2007: .939 OPS
June 2007: .569 OPS
May 2008: 1.077 OPS
June 2008: .831 OPS
His dip two years ago, actually, was even more epic than his dip this season:
May 2009: .978 OPS
June 2009: .701 OPS
As the Red Sox are weighing the value of signing Bay to a multiyear contract, however, it's not his streakiness that's the issue. That's the given. The issue is this: Before this season, Bay hadn't had a .900-plus OPS for an entire year since 2006. With his 31st birthday behind him, might his strong season this season be a sign of things to come -- or an anomaly?
Among the possible indicators:
2007: 23.0 percent
2008: 20.5 percent
2009: 25.4 percent
(That doesn't tell you much.)
2007: 9.6 percent
2008: 12.1 percent
2009: 14.7 percent
(That's a good sign but still doesn't say much.)
2007: 18 percent
2008: 17 percent
2009: 18 percent
(Too consistent to be an indicator.)
Home runs per fly ball
2007: 9.6 percent
2008: 12.4 percent
2009: 17.3 percent
There it is: Percentage-wise, Bay saw almost twice as many fly balls sail over the fence this season than he did during his lackluster 2007 season. (Bay hit just 21 home runs and OPS'ed .746 in 2007.)
The truth is somewhere in the middle. Bay has a career HR/FB ratio of 13.4, somewhere between his extremes from 2007 and 2009 -- and somewhere pretty close to the 12.4 percent he had in 2008.
Bay hit 31 home runs and OPS'ed .895 in that 2008 season, numbers that ranked him 27th and 21st, respectively, in the major leagues. His numbers, actually, compared pretty favorably to those of Josh Hamilton in 2008:
Bay: 31 HR, .373 OBP, .522 SLG
Hamilton: 32 HR, .371 OBP, .530 SLG
Bay got a little bit lucky in 2009 -- but he didn't get all that lucky. He's still a 30-100 hitter with the ability to put up a .900 OPS.
Whether he'll still be doing that four years from now, though, is the question the Red Sox have to answer.