What's Up Tonight in MLB: Harper slugging for the record books; Strasburg hoping to end struggles

An exciting month in the majors is set to wrap up this weekend as the calendar flips to June. Here's what you need to be watching in the final days of May:

Dodgers and Cardinals clash in NLDS rematch

A pair of division leaders will renew their rivalry Friday as the Los Angeles Dodgers and St. Louis Cardinals open a three-game series in a rematch of last year's National League Division Series.

The Cardinals, who advanced to the NLCS with a 3-1 series win last October, enter the weekend as winners of three of their last four games, and own a major-league best 31 wins. They are, however, without the services of slugger Matt Adams, who hit the go-ahead three-run home run off Clayton Kershaw in Game 4 of the NLCS. Adams is expected to miss the next three-to-four months with a torn right quadricep.

After being shut out during a three-game series sweep by the San Francisco Giants last week, the Dodgers have won four of their last six and sit atop the NL West at 28-18. Los Angeles will be without their big guns this weekend after both Kershaw and Zack Greinke pitched earlier this week against Atlanta.

Memorable May

Washington Nationals slugger Bryce Harper has three more games, all against the Cincinnati Reds, to try and hit four home runs if he hopes to tie Barry Bonds's NL-record 17 home runs in the month of May.

The 22-year-old has been on a torrid pace, blasting 13 home runs over his last 63 at-bats. He sits four home runs away from tying his career high after just 47 games.

Harper's 13 home runs - more than the Atlanta Braves have hit in May - are the most in a single month in franchise history. He's also the first player since Alex Rodriguez in 2003 to hit 13 home runs in a 22-game span. A-Rod claimed the AL MVP that season.

Other impressive May performances:

• Prince Fielder: 42 H, 7 2B, 9 HR, 28 RBI, .382/.430/.691
• ​Max Scherzer: 5-1, 1.67 ERA, 56 K, 0.91 WHIP
• A.J. Burnett: 5-0, 1.82 ERA, 39 K, 1.11 WHIP
• San Francisco Giants: 20-7, 3.31 ERA, .298 AVG

Looking to rebound

A pair of young arms will be under the microscope this weekend as they attempt to rebound from poor starts.

Nationals right-hander Stephen Strasburg has been terrible this season, going 3-5 in nine starts while authoring a 6.50 ERA. He was shelled for six runs (five earned) on Saturday, the third time in his last four starts that he's failed to reach the fifth inning. The 26-year-old takes the mound Friday against the Reds and another poor start could force Washington to temporarily pull their young star from the rotation.

While New York Mets right-hander Matt Harvey has made a remarkable return from Tommy John surgery, the 26-year-old is coming off one of the worst starts of his career, followed by concerns about dead arm from manager Terry Collins. Harvey was tagged for seven runs in four innings by the Pittsburgh Pirates. Collins considered skipping Harvey's next start, though he'll be on the mound Friday against the Miami Marlins.