Who will throw next perfect game?

But there are certain attributes that appear to help increase a starter's chances of joining the 20 pitchers who have thrown perfect games.

Yankees manager Joe Girardi, who caught David Cone's perfect game in 1999, said a pitcher needs to throw first-pitch strikes, to have "swing-and-miss stuff" and to be supported by a good defense. His pitching coach, Dave Eiland, believes that defense is the key for any pitcher with good command.

"If somebody's on top of his game, anybody can do it," Eiland said.

The balancing act is for a pitcher to keep the ball out of play via the strikeout -- the last 14 perfect games have featured an average of 9.5 strikeouts -- without going too deep in the count. Of the 10 perfect games for which there is pitch-count data available on baseball-reference.com, the starters averaged 107.2 pitches per game.

Back when Indians closer Kerry Wood was a starter with the Cubs, he threw arguably the greatest game ever pitched that wasn't a perfect game, a 20-strikeout shutout of the Astros on May 6, 1998, in which he allowed just two baserunners in his fifth career start. Wood said it's important to have a large arsenal to keep hitters guessing.

"You've got to have three pitches that you're throwing where you want them," Wood said.

A pitcher can never be expected to throw a perfect game, but with these guidelines in mind -- first-pitch strikes, swing-and-miss stuff, multi-pitch repertoire and good team defense -- here are the top candidates to attain perfection.

Brett Anderson, A's:The young Oakland lefthander has a 1.88 ERA and just four walks in 28 2/3 innings. His 0.94 WHIP would lead all American League starters if he had thrown enough innings to qualify, and on Saturday Anderson proved he's healthy again. After missing five weeks with a forearm strain, he threw 5 2/3 shutout innings in his return, allowing three hits and no walks. The A's defense, which backed Braden earlier this month, ranks fourth in the majors per Baseball Prospectus' Park-Adjusted Defensive Efficiency (PADE).

Matt Cain and Tim Lincecum, Giants:Supported by baseball's best defense, according to PADE, the Giants' top two starters are always a threat. Lincecum, the two-time NL Cy Young winner, leads all major-league starters in swing-and-miss percentage (30.3). In his last start on Friday, Cain threw a complete-game shutout, the third of his career, allowing just one hit and no walks to the Diamondbacks.

Neftali Feliz, Rangers:Given that 2010 is the first year in history to feature two perfect games, chances are the next one probably won't come until at least 2011, by which time the Rangers' fireballing closer will likely be inserted into the rotation. That is the club's long-term projection for him, and with a career WHIP of 0.78 and K/9 of 10.4, Feliz's stuff is as electric as anyone's. Plus, Texas' lax pitch-count limits mean the young hurler could be given the chance to go the distance.

Zack Greinke, Royals:At this rate, Greinke may have to throw a perfect game just to get a win -- he's 1-6 this year despite a 3.39 ERA -- but the '09 AL Cy Young winner is as dominant as anyone in baseball when he's at his best. He had a 38-inning scoreless streak in '09, a league-leading 1.07 WHIP and three shutouts.

Felix Hernandez, Mariners:In '09 the precociously talented Hernandez, then just 23, put together a consistent season in which he went 19-5 with a 2.49 ERA and allowed an AL-best 7.5 hits per nine innings. He's already made 45 career starts in which he's pitched at least seven innings and allowed no more than one earned run, including a one-hit, two-walk shutout of Boston in '07.

Ubaldo Jimenez, Rockies:There's seemingly nothing Jimenez can't do this season. The hardest-throwing starter in baseball (96.1 mile-per-hour average fastball velocity) is 9-1 with a 0.88 ERA and threw a no-hitter against the Braves in April. That no-hitter was marred ever so slightly by six walks, but his control has since improved: He's walked only four batters in his last three starts, a span of 23 innings.

Jon Lester, Red Sox:Boston's de facto ace (6-2, 2.97 ERA, 1.13 WHIP) already has a no-hitter to his name. Lester leads AL starters in allowing only 6.3 hits per game and is fourth in the league in swings that result in a miss (25.4 percent). His Achilles' heel has been a high-walk rate of more than three walks per game, but he has made nine career starts of at least six innings without walking anyone, including a complete-game victory over the Twins on May 20.

David Price, Rays:The Rays have ranked among baseball's best defenses for the past three seasons, and Price has the young rotation's most electric collection of pitches. His fastball is in the high-90s, his slider made the Red Sox look silly in the '08 ALCS and his curveball is rapidly improving. Price notched his first complete-game shutout against the slugging Blue Jays in late April.

Ricky Romero, Blue Jays:Romero has broken out in his sophomore season, going 5-2 with a 3.14 ERA, 1.20 WHIP and .229 batting average against through 77 1/3 innings and carrying a no-hitter into the eighth inning against the White Sox in April. Thanks to a fall-off-the-table changeup, he gets more swings and misses than any other AL starter (27.1 percent). He has the same knock as Lester: too many walks. He's only made one career start in which he didn't walk anyone, but he has good control on his best days, issuing only seven bases on balls in his four starts this season of at least eight innings.

Stephen Strasburg, Nationals:No, he hasn't thrown in any major-league games yet, much less come close to completing a perfect one, but what limits would you place on him? This is an exercise in potential and few, if any, have the upside of Strasburg, whose minor-league record is sparkling (6-2, 1.43 ERA, 0.80 WHIP, 10.7 K/9) and who'd need only one dazzling start to make it happen.