On Tuesday night, the baseball world recognized Jacoby Ellsbury as one of the defensively elite players in the game. The 28-year-old received a Gold Glove, an accolade that conferred upon him the status of the top defensive center fielder in the American League. He became the first Red Sox outfielder since Ellis Burks in 1990 to receive the award.

As is usually the case with the highly subjective voting process, it was fair to argue with the characterization. In particular, fellow finalist Austin Jackson had an excellent case as the best defensive center fielder in the American League.

Nonetheless, there was no disputing the notion that Ellsbury had a brilliant defensive season, whether just by watching him chase down fly balls in the gaps, or by the use of traditional defensive measures or more advanced defensive metrics. Through just about any prism, Ellsbury was one of the best defensive center fielders in the game.

Yet, while observers viewed this season as a defensive coming of age, Ellsbury was less impressed by his own body of work.

“It’s like I felt like I’ve done in the past. Nothing for me has changed, really,” he said of his defense during the season. “I feel like I’ve done the same thing I’ve always done. … You just play the way you’ve been doing your whole life. It’s instincts.”

Others felt differently. Ellsbury’s emergence as a Gold Glover was all the more intriguing based on the fact that, just two years ago, in his last full season as a center fielder, he was viewed in some corners as one of the worst defenders at his position in the game.

And those numbers weren’t entirely baseless. There were times when Ellsbury would have an imprecise first step that cost him plays. Moreover, he positioned himself deep in center and had a tendency to defer to more veteran outfield corner players (J.D. Drew and Jason Bay) on some fly balls. And, of course, Ellsbury is never going to be described as someone with a cannon for an arm.

The result was that the advanced metrics in the public domain were hard on the center fielder. The UZR (ultimate zone rating) stat that has been popularized on Fangraphs.com suggested that Ellsbury had cost the Red Sox 9.7 runs with his play in center field, a total that ranked him 28th among center fielders who had played at least 500 innings at the position.

Internally, the Sox viewed him differently, seeing an average to slightly above-average defensive center fielder whose tremendous speed allowed him to outrun some of his mistakes. Even so, the team acknowledged that there was room for improvement, particularly with more direct route running.

But in 2011, the view of Ellsbury was dramatically different. He measured consistently as one of the better defensive outfielders in the game. The same stats that once pegged him as below average instead identified him as the most impactful center fielder in the game, crediting him with having saved 15.6 runs more than the average center fielder.

The plus/minus system used by John Dewan’s Fielding Bible similarly pointed to a dramatic leap forward for Ellsbury. He had been ranked 29th among big league center fielders in 2009, having been eight runs below average at this position. This year, he was viewed as being eight runs better than the average defender at his position, sixth best in the majors.

(A couple of quick caveats about UZR and plus/minus: Front office executives of multiple clubs feel that the two statistics remain somewhat flawed and struggle to account for elements such as park effects as well as complementary players. Moreover, both the proponents of those stats as well as those responsible for tracking defense for baseball teams suggest that defense is best judged over three-year spans, as the relatively small sample of the number of plays in any given year can result in huge statistical swings.)

More traditional ways of evaluating defense suggested that Ellsbury had a remarkable year. He became the first everyday Sox center fielder to turn in an errorless season. His 1,358 1/3 defensive innings without an error were the most ever by an American League center fielder. He led the AL in innings and putouts (388) at the position.

Certainly, the eye test suggested a player who came into his own at a critical position. While Ellsbury remained superior tracking balls into gaps as opposed to those that required him to break toward or away from the plate, he made strides in every defensive area this year.

“He’s different because he’s developed. Every year he’s gotten better,” former Sox first base and outfield coach Ron Johnson, who managed Ellsbury in Triple-A in 2007, said during the season. “You can really see where he’s come from, since Pawtucket back in the day to now. He understands hitters, he understands pitches. You see him move with the swings, with the location.

“I think that plays just from experience. It allows him to get better jumps on balls in the outfield. I think he’s done a great job. You would have to say he’s improved, as I think we hoped he would, just from the experience of playing and all that athleticism that he has.”

This spring training, the Sox charged Ellsbury with the task of being the quarterback of the outfield. He was precisely that this season, asserting himself and essentially catching anything that he can while his corner outfielders defer. 

“What I’ve really been impressed with from Jake is his ability to run the outfield,” Johnson said. “He wants to be in the middle. He wants to run the show. That’s good stuff.”

Those traits were apparent to the big league managers and coaching staffs responsible for voting for the Gold Glove award. And with Ellsbury’s recognition as one of the top defenders in the game comes yet another reminder of how comprehensive an impact he made in 2011, something that suggests that he may not be done collecting postseason hardware.