Comparison shopping: Bay vs. Holliday

The most storied position in Boston Red Sox history is currently vacant.

If the Red Sox don't sign Jason Bay to an extension during their exclusive negotiating period over the next 15 days (which seems unlikely), they will go into the winter with a gaping hole in left field. Both sides have expressed interest in Bay's return, but another big-name left fielder is also looming on the open market.

Among active players, Matt Holliday has the fifth-highest career batting average and 10th-highest OPS. He is also 15 months younger than Bay. With gaudy career numbers and a torrid stint with the St. Louis Cardinals, Holliday is the biggest name on the free agent market. But who is the better fit for the Red Sox? At first glance, the numbers all point to Holliday. But after taking a closer look at three key factors -- the Coors Field effect, performance late in games and on-base ability -- the decision is not so clear.

Finding a level playing field

Matt Holliday is a .357 career hitter at Coors Field, with 18.2 plate appearances per home run. Everywhere else, he is a .290 hitter with 31.1 plate appearances per homer. Look at it this way: At Coors Field, Matt Holliday is Ted Williams. Elsewhere, he's basically Mike Greenwell.

Clearly, playing at Coors helped Holliday. But is that a legitimate concern for the Red Sox? Is Holliday among the elite hitters or is he a product of his environment?

First, a note on the Coors Field effect. From 1995 to 2001, the Rockies hit .328 at home (best in baseball by .036) and .248 on the road (worst in baseball). Starting in 2002, the Rockies began storing balls in an atmosphere-controlled humidor to help counteract the effects of the environment. Since then, the Rockies are hitting .296 at home, still best in baseball, but just barely better than Boston's .292 batting average at Fenway. Colorado's .243 batting average on the road over that span is still worst in baseball. So it's still advantageous to hit at Coors Field, just not the way it was when Larry Walker roamed the outfield. Holliday, who debuted in 2004, has played his entire career in the humidor era of Coors Field.

Holliday's 2009 season was a fascinating -- if somewhat inconclusive -- look into his post-Coors career. Splitting the season between the Oakland A's and Cardinals, he played home games in pitcher-friendly parks. While hitting behind the likes of Jason Giambi and Jack Cust, Holliday hit .286 at Oakland Coliseum. Then in St. Louis, he hit .377 at Busch Stadium, but did so with Albert Pujols hitting in front of him. In all, he hit .326 with 16 homers at home in 2009, similar to his 2008 line in Colorado.

Until coming to Fenway, Jason Bay played in PNC Park, a neutral park that may lean a bit toward pitchers. Over the course of his career, his home and road numbers are remarkably consistent. So how do we put Bay and Holliday on an even playing field? It's easiest to look solely at their career numbers on the road. In that case, give the nod to Bay. With a career .898 OPS on the road compared to Holliday's .808, Bay (106) has more than twice as many road home runs as Holliday (52) in just 81 more at-bats.

Who will produce when it matters most?

Ultimately, the biggest difference between the Red Sox and New York Yankees last season was offense late in games. The Red Sox hit just .243 from the seventh inning on, their worst mark since hitting .241 in 1994 when they finished the strike-shortened season 54-61. Jason Varitek (.185) and David Ortiz (.199) were the primary offenders, but Bay (.235) and Dustin Pedroia (.231) did little to help. Meanwhile, the Yankees led the majors with a .293 batting in the seventh or later.

Even more alarming, the Red Sox hit just .240 in "close and late" situations, defined by baseball-reference.com as the seventh inning or later with the hitting team tied, ahead by one or with the tying run at least on deck. That is the second-worst such average for the Red Sox over the past 35 years, only better than a .225 average in 1991. Meanwhile, the Yankees hit an MLB-best .316 in close and late situations. So which player will better help close that gap?

At first glance, Bay does not appear to be the answer. He's a career .258 hitter in the seventh inning or later, compared to .289 in the first six innings. In close and late situations, he has hit just .242. Compare that to Holliday's career averages of .306 in the seventh inning or later, and .302 close and late. The answer seems pretty simple, right? Not so fast. Holliday has the superior overall resume, but Bay's career totals are a bit misleading.

Quite simply, Bay was not part of the problem for the Red Sox. Sure, he hit just .235 in the seventh inning or later. But he hit .299 in that situation when the games were close. Over the past two seasons, he is hitting .309 close and late, compared to .211 in his first five seasons. It's all part of the larger theme to Bay's 2009 season. His offensive production varied greatly depending upon the margin of the game.

Remember the claim -- only partially warranted -- that Alex Rodriguez produced only in blowouts? Well, think of Bay in 2009 as the anti-A-Rod. When the game was within two runs, Bay hit .300 with 25 homers and 85 RBIs. With a margin of three runs or greater, Bay hit .207 with 11 homers and 34 RBIs. Holliday hit .303 when the margin was within two runs, but .332 otherwise. In other words, in close situations, Bay was arguably the better player last season.

Getting on base

Among position players, J.D. Drew is easily the most high-profile free agent signed by the Red Sox during the Theo Epstein era. Apart from the ongoing carousel of shortstops, every other major free-agent signing has been about retention and the Red Sox have generally refused to overpay for free-agent bats. So if the Drew signing tells us anything, it's the high value Epstein places on getting on base. Over the past three seasons, only seven American League players have a higher on-base percentage than Drew (Kevin Youkilis is one). In 2009, Drew finished third in the AL in walks per plate appearance behind only Nick Swisher and Carlos Pena.

So how do Bay and Holliday stack up? It's another area in which Bay evens the score. Between the two, the common perception would seem to give Bay the nod in power, while Holliday has the edge offensively. But as with Drew, Bay's ability to draw a walk is a silent weapon.

Bay has averaged 7.9 plate appearances per walk during his career, well above Holliday's 11.3 plate appearances per walk. That difference has negated much of Holliday's edge in batting average. Despite a career batting average .038 points higher than Bay's, Holliday's career on-base percentage is just .011 points higher. This, of course, doesn't even delve into the possible effects of Coors Field.

The real difference is against right-handed pitching, which comprises about 75 percent of plate appearances. Holliday is a far more impatient hitter against righties (12.8 PA per BB) compared to lefties (8.0 PA per BB). Holliday has been a more consistent on-base presence than Bay, but how that will extend beyond Coors Field is open for debate.

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