SEATTLE — Even after a recent torrid stretch that has seen him lift his batting average to a respectable .258, Coco Crisp’s season can’t be truly measured on the stat sheet.

The stats can show that he has boosted his average 37 points in the last 11 games, that he’s second in the American League with four bunt hits and tied for fourth with four sacrifices, and that he’s been successful in 15 of his 19 stolen-base attempts.

But the true measure of Crisp’s 2007 season is found in more arcane numbers, not readily available or found on a Web site. According to data compiled and maintained by one major-league club, Crisp is playing the best center field of any outfielder in the major leagues — and by a long shot.

The club, which asked not to be identified, uses a complicated metric to measure defensive play, including range and coverage. Based on its findings, tabulated monthly, Crisp is playing at a “plus-24” level in center field, meaning that through the end of May, Crisp had already recorded putouts on two dozen more players than the average center fielder.

While the data can’t be easily extrapolated for an entire season — there’s no guarantee that Crisp will finish at a plus-72, for example — he’s on pace to easily top last year’s best full-season grade, a plus-30, earned by Willie Taveras, then with Houston.

Similarly, Crisp could equal the best numbers achieved by Mike Cameron and Andruw Jones, each of whom had graded out near a plus-60 in their prime.

“Regardless of what the numbers say,” said Red Sox manager Terry Francona, “ I know how well Coco has played out there. Sometimes the numbers can fool you a little. But I can see with my own eyes how good he’s been.”

Crisp wasn’t nearly as proficient in the field last year, his first in Boston. The spacious center field in Boston was new to him and Crisp’s play was tentative at times.

“If you ask me,” said one scout recently, “I think he just needed a year to get used to center again (Crisp had played left field in 2005, his final year in Cleveland). It takes some adjusting — the ball comes off the bat differently. For one thing, it’s hit right at you, and that can be tricky. But he’s a much better center fielder this year than a year ago.”

When the Sox dealt for Crisp after the 2005 season, they envisioned him as a worthy successor to Johnny Damon, who left as a free agent to the New York Yankees. What they got, instead, was someone seemingly unsuited for both of Damon’s roles — center fielder and leadoff hitter.

At the plate, Crisp wasn’t nearly patient enough. In the outfield, he showed only brief flashes. An astounding diving catch against the New York Mets’ David Wright last June was unquestionably the season highlight. But that sort of highlight-reel catch was infrequent.

This season, they seem to be an almost weekly occurrence.

“I think he’s just more familiar, more comfortable, more confident out there,” said third base coach DeMarlo Hale, who also doubles as the Red Sox’ outfield instructor. “He’s a talented young man with the speed to close on a ball quickly. And we’re seeing that more and more.”

Crisp, who has declined to be interviewed in recent weeks, reported to spring training as a more assertive defender. He’s spent more time going over scouting reports to help him better position himself and is more knowledgeable about his own pitchers, giving him help in anticipating where a pitch might be hit.

A season ago, from his perch in the dugout, Hale had to direct Crisp in the outfield from batter to batter. This year, Crisp has often adjusted his positioning in center before Hale has a chance to move him.

“And he’s taken more of a leadership role out there with Manny (Ramirez) and J.D. (Drew),” Hale said. “He’s communicating with them and making sure they’re covering the space between one another.”

Even by conventional measures, Crisp’s play has been outstanding. Going into last night, he had yet to commit an error in center, and the number of putouts he had recorded (205) without an error was second only to the Mariners’ Ichiro Suzuki, who had 218.

smcadam@projo.com