Back at the end of April, I compared then soon-to-be free agent outfielders Jason Bay and Matt Holliday. I concluded that Holliday was the better player out of the pair, writing:

"Holliday is the better all-around player. He is a year younger, and much better on the bases and in the field. Bay has been the more productive hitter, but he is defensively challenged and not quite as valuable overall. Whether Holliday can perform in Oakland, though, will dramatically affect his and Boras' bank account. In a weak market, he could be the Mark Teixeira of the '10 offseason; the New Yankee Stadium would be a nice destination for him, production-wise. Holliday, who will earn $13.5M in '09, could end up regretting his decision to turn down the Rockies' four-year, $72M offer if he really does struggle and the economy does not rebound. Odds are, though, that will not happen"

A lot has changed since then. At the time of the article, Bay had been raking for the Boston Red Sox and Holliday was off to a terrible start with the Oakland A's. Revisiting the debate now, it is clear that Holliday is the more attractive free agent and the player worth taking a chance on.

UmpBump's Sarah Green knocked it out of the park in her analysis comparing each player in a column in the Boston Metro today.

Green:

"On defense, Bay was the second-worst left fielder in baseball last year. According to Ultimate Zone Rating, he was only slightly better than the execrable Ryan Braun. And Braun is 26, cheap, and offers the kind of bat that more than makes up for his glove.

Bay is 31, has a bat that barely counterbalances his fielding, and is a free agent. Because the market overvalues power hitting and undervalues defense, he's likely to command a high salary, a lengthy contract -- or both. And as the excellent blog USS Mariner recently demonstrated, Bay's "classic old player skills" make him "eerily reminiscent" of Richie Sexson, a slugger who flamed out not long after inking a big-money deal with Seattle at age 29."

She hit the nail on the head there in regards to fielding. Bay is a defensively challenged outfielder who is going to end up as a designated hitter before his next contract runs up. UZR is known to fluctuate wildly from season to season, but over the past three years, he has produced totals of -11.5, -18.4 and -13.9 in the statistic. For his career, he has been worth -52.1 runs below an average outfielder, and, while the exact extent of his poor defense is not known, it is clear that his poor glove work hurts his overall value.

Bay can sure hit. The 30-year-old posted a line of .267/.384/.537 with 31 homers and 119 RBIs in his first full campaign in Boston. He managed only 3.4 WAR (still worth $15.3-M), though, because of his defense. Given his offensive production, that total, while excellent, is surprising.

Holliday, on the other hand, is a complete baseball player. He definitely got off to a rough start in Oakland, batting .286/.378/.454 with only 11 home runs. Many attributed his power drop off to moving out of known band box Coors Field, leading to several articles written about how he was a product of his home-hitting environment. After being traded to the St. Louis Cardinals for Brett Wallace and two other players in mid-summer, though, he tore up the Senior Circuit in the second half. In fact, he may have been the National League's Most Valuable Player in the time span that he was with the Cards. Much to the liking of agent Scott Boras, he hit .353/.419/.604 with 13 home runs, a 168 OPS+ and 55 RBIs in 270 plate appearances.

Sure, Holliday made a monumental error in the playoffs. He lost a ball, which should have been caught, in the sun, hurting St. Louis' chances of winning a crucial Division Series game against the Los Angeles Dodgers. Overall, though, he has been among the best defensive left fielders in the majors over the past several seasons. When factoring in batting, fielding and positional factors, he has been worth 23.7 WAR/$73.6-M since 2007.

In other words, Holliday is considerably better than Bay overall and is the best bat available on the market. Boras' asking price is going to be astronomical--he compared Holliday to Mark Teixeira when speaking to the media yesterday--but if there is an outfielder worth making a length investment in, it is indeed him.