May was the second month of the season, but there was plenty of first-rate action on the field. Two players racked up the only four-homer games of the season, and there were several milestones reached by future Hall of Famers. There was also a managerial hiring, a high-profile retirement and the most anticipated Major League debut of the season. Without further ado, MLB.com brings you the prime plays from May.
Mets pitcher Al Leiter became the first pitcher in the Major Leagues to defeat all 30 clubs Tuesday night
by beating the Diamondbacks by a 10-1 final score.
Seattle's Mike Cameron tied a Major League record by hitting four homers against the White Sox, becoming the first Mariner to accomplish that feat. After the game, he said it was "an unbelievable feeling."
Anaheim's Darin Erstad kept his team rolling and sent Toronto in the opposite direction with some homer heroics on the road.
San Francisco's Ryan Jensen turned an emergency relief outing into a brush with history, by taking a combined no-hitter into the eighth inning of a 3-0 win.
Baltimore's relief staff has been surprisingly effective, even though it consists of several anonymous rookies.
Odalis Perez has proven that he was more than an afterthought in the trade that sent him to Los Angeles.
Oakland's Barry Zito agreed to a three-year contract extension with the A's, keeping the talented southpaw with Oakland through 2005.
Cleveland's Brady Anderson returned to Baltimore for the first time since being released by the Orioles and scored the winning run against his former team.
Veteran reliever John Franco learned that his season and his career could be over because of an elbow injury.
The Rockies unveiled an innovative method of keeping down the offense at Coors Field that involved baseballs and humidors.
Ryan Dempster became Florida's all-time leader in wins with the modest total of 38.
San Francisco's Kirk Reuter won the 100th game of his career and beat the Mets for the first time in one fell swoop.
Chicago's Mark Buehrle has quietly emerged as one of the American League's best pitchers, evidenced by his league-leading win total.
Andres Galarraga got some good news on the health front, as the Montreal slugger learned that his body was free of cancer.
The Devil Rays broke a franchise-record 16-game losing streak with a walk-off home run by Randy Winn. That skid was the longest in the Major Leagues since 1988.
Pedro Martinez, who has been one of the best pitchers in baseball over the life of his career, announced that he wants to end his career with the Red Sox.
Boston's Manny Ramirez injured his finger in a play at the plate and was expected to miss a month of the season.
Joe Torre reached a major milestone on Mother's Day, when the Yanks won to give Torre 1,500 career wins.
Highly touted rookie Hank Blalock was sent down to the minors to regain confidence and his batting stroke.
Jose Canseco announced his retirement from the game, ending his career 38 homers shy of the 500 mark.
Ruben Sierra is putting together an impressive comeback story, as improbable as it may seem.
A lot has changed in Los Angeles since Mike Piazza became an ex-Dodger, including the composition of LA's roster.
Pittsburgh's Mike Williams hasn't gotten a lot of attention,but he's quietly become one of the most effective closers in baseball.
Roger Clemens tied Robin Roberts on the all-time win list and immediately set his sights on another pair of all-time greats.
Chicago's Tony Graffanino, who usually makes a contribution with his glove, came up with a career night at the plate.
Tony Pena, Kansas City's new manager, met his players for the first time.
Florida's Josh Beckett has showed some of the poise and patience that has made him a top pitching prospect.
Dave Dombroski pulled off his first trade as general manager of the Tigers, sending Jose Macias to Montreal in exchange for Chris Truby.
C.C. Sabathia, Cleveland's second-year starter, survived a scary encounter when he was robbed at gunpoint during a night out on the town.
Dave Littlefield has made his presence felt during his short tenure as Pittsburgh's general manager.
Jason Giambi made his biggest impact in Yankee pinstripes by swatting a game-winning grand slam against Minnesota.
Jose Rijo has put together such a stunning comeback story that he has even begun to surprise himself.
Arizona's Erubiel Durazo had a career night at the plate with nine RBIs in a 12-9 win over Philadelphia.
Roger Clemens continued his march toward immortality by passing Bert Blyleven on the all-time win list.
Kris Benson looked dominant again for the first time since an elbow injury threatened his once-promising career.
Former Houston manager Larry Dierker had his number retired by the franchise, and he said it was the most special day of his career.
Seattle's bus caught fire on the way to the Boston airport, but nobody was hurt in the harrowing incident.
In response to a tabloid article, Mike Piazza chose a public forum to halt gossip about a private issue.
Jeremy Giambi followed his brother to the East Coast when he was traded from Oakland to Philadelphia.
Randy Johnson faced off against Barry Bonds and recorded his 3,500th strikeout in an exciting game for the ages.
The Dodgers' Shawn Green homered four times and went 6-for-6 in an amazing display of hitting. "It felt incredible," he said.
The Cubs' Mark Prior looked back on his Major League debut and realized his life had changed forever.
Barry Bonds crushed yet another historic home run to tie Mark McGwire for fifth on the all-time charts.
Ken Griffey Jr. returned to the Reds' active roster for the first time since the first week of the season.
Pedro Martinez shut down the Yankees and then scoffed at the idea of a Curse of the Bambino.
Kansas City closer Roberto Hernandez became just the 15th pitcher in Major League history to record 300 saves in his career.
Seven-time All-Star Craig Biggio started off slow but refuses to accept his sudden slide.
The Blue Jays traded veteran reliever Dan Plesac to Philadelphia for hard-throwing reliever Cliff Politte.
Cleveland starter Bartolo Colon pitched a complete game four-hitter in a 3-1 win over Toronto.
Shawn Green continued his streaky week with two homers in a game, setting a record for most homers (7) in a three-game span.
After a slow start to the season, Tino Martinez continued his hot month with a pivotal home run in a 4-3 win over Houston.
Cincinnati's Aaron Boone belted two homers, one in extra innings, to bury the home-standing Marlins.
The Cubs' Matt Clement pitched six hitless innings but had to settle for a complete game two-hitter against Pittsburgh.
A Sports Illustrated story on steroid abuse sent shockwaves through the baseball community.
Mark Bellhorn earns some attention with the first grand slam of his Major League career.
Houston's Richard Hidalgo had a big day at the plate in Chicago, going 4-for-4 with two singles and two home runs.
Tampa Bay's Greg Vaughn had the best day of his dismal season, driving in the tying and winning runs against Oakland.
Spencer Fordin is a reporter for MLB.com and can be reached at email@example.com. This story was not subject to the approval of Major League Baseball or its clubs.