Bay's bat will be missed

With Red Sox general manager Theo Epstein seemingly done with his offseason shopping, barring a minor tweak or two, ESPNBoston.com's Gordon Edes is looking at the team position by position. Today, Edes breaks down the outfield.

This is the position most ripe to generate controversy in 2010, with the Red Sox opting to let Jason Bay sign with the New York Mets for a better offer, rather than giving him the fifth year he was seeking. They made a take-it-or-leave-it offer to free-agent outfielder Matt Holliday, and when he balked, they used the same money on starting pitcher John Lackey, giving him five years even though he has perhaps more red flags, with respect to health, than Bay, who the Sox decided would be DH material by that time.

The Sox then chose a much more modest bat, center fielder Mike Cameron, and decided to shift Jacoby Ellsbury to left, which they believe will significantly upgrade them defensively at both spots. But will the imagined gains in catching the ball in the outfield outweigh the loss of Bay's bat? Skeptical Sox fans have their doubts.

"It was more of a business decision," manager Terry Francona said. "Theo [Epstein] and those guys have to draw a line, a tough line, on the present and the future. They do a fabulous job.

"Sometimes we make decisions … that are not popular. Sometimes we're wrong. But that's the game of baseball."

2009 performance: One of Bill James' favorite stats is something called "win shares," which he devised as a way to relate a player's individual statistics to the number of wins he contributed to his team. An MVP-caliber season generally translates to 30 or more win shares. Minnesota catcher Joe Mauer led the AL with 32 and was indeed elected MVP.

Finishing second with 29? Jason Bay, who not only failed to get a trophy but also was allowed to walk by the Red Sox. Bay was second in the AL with 119 RBIs. He hit .360 with runners in scoring position, hit .533 with the bases loaded and was the only AL left fielder with an OPS over .900 (.925). In the stats many analysts give great weight to (see table for definitions), Bay also excelled: runs created (second), secondary average (second), isolated power (third), offensive winning percentage (fifth).

And yet, for all the statistical splendor engendered in his performance, the Red Sox factored in his negative defensive metrics (minus-11.9 UZR/150 rating -- which measures the number of runs above or below average a fielder is per 150 games), anticipated that the 31-year-old's offense would decline over the course of five years, and elected to move on.

Ellsbury, meanwhile, won a stolen-base title, stealing 70 bags and succeeding on 85 percent of his attempts. (He was caught 12 times). Since 1980, a player has stolen 70 or more bases 36 times, but Ellsbury became just the eighth player in that span to convert 85 percent or more of his chances, and the first since Marquis Grissom in 1992. He also became a .300 hitter for the first time (.301), while his OBP (.355) and slugging percentage (.415) each improved by about 20 points over 2008. Ellsbury also showed more patience at the plate, finishing eighth in the league in percentage of first-pitch swings (12.1 percent). He also finished fifth in the league in hitting with a two-strike count, batting .268. These are all very positive signs for a player in his second full season. The power hasn't come (8 HRs), but the Sox still think he could develop into a 15- to 20-home-run player.

J.D. Drew's 24 home runs were the most for him since 2004, and his slugging percentage of .526 was second only to Bay's among qualifying AL outfielders. He was hitting just .252 at the break, but his .999 OPS in the second half led all AL hitters. And his UZR/150 rating of 15.7 led all major league right fielders in that defensive metric.

Departures: Bay left as a free agent. Rocco Baldelli left as a free agent. Joey Gathright left as a free agent. Brian Anderson was non-tendered and became a free agent.

Newcomers: Jeremy Hermida was acquired in a trade with the Marlins. Cameron signed as a free agent. Infielder-outfielder Bill Hall was acquired in a trade with the Mariners.

Upgrade over 2009?: No.

Yes, they should catch more balls, but the Sox's outfield defense with Bay in left and Ellsbury in center was more than adequate to get the team into the postseason. James, who was uncannily accurate on his projection for Cameron in 2009, is forecasting the 37-year-old to strike out 100 more times than he walks in 2010 (171 to 71) while posting a .328 OBP. That would have ranked him 48th among qualifying big league outfielders in 2009. Cameron should hit 20 or more home runs for the fifth straight season.

Ellsbury's move to left field should save him some wear and tear, a benefit to his running game. Drew is 34, which means that Hermida, who did not come close to meeting projections in Florida, should get plenty of at-bats. At age 26, Hermida may yet become a productive major league hitter. Hall will fill the role of fifth outfielder.

But Bay's bat will be missed.

Gordon Edes is ESPNBoston.com's Red Sox reporter. He covered the Red Sox for 12 years and has reported on baseball for 25 years. Ask a question for his next mailbag here.