5 must-watch series in MLB's second half

From crosstown rivalries to key dates in David Ortiz's farewell tour, the weeks and months ahead for MLB promise to deliver plenty of intrigue and excitement. As the first week of the second half of the season comes to a close, here are the five series we're looking forward to the most for the remainder of the season:

Mets at Marlins: July 22-25

Fans will get a dose of playoff-like baseball Friday when the Marlins host the Mets for three games in Miami. The matchup has plenty of storylines, the least of which includes Ichiro Suzuki's pursuit of 3,000 hits. Suzuki enters the series opener four hits shy of becoming the exclusive club's 30th member, and he'll get an opportunity to reach the milestone amidst a NL East showdown featuring two clubs chasing a playoff spot. The Marlins hold a 1 1/2-game lead over the Mets for the second wild card. Strangely enough, this weekend also marks Jose Reyes' first visit to Miami as an opposing player since getting dealt from the Marlins to Blue Jays in the winter of 2012.

Cubs vs. White Sox: July 25-28

Granted, this matchup looked considerably more compelling back in May, when both clubs were among the top teams in baseball and one White Sox executive was dreaming of a World Series "civil war." Though the club has slowed from its record-setting pace, the Cubs remain a juggernaut and championship favorite, while the South Siders are scrambling to stay afloat as they consider selling off pieces at the deadline. Either way, this home-and home-series has big implications for both clubs, beginning with Jake Arrieta at U.S. Cellular Field and ending with Chris Sale squaring off against John Lackey at Wrigley.

Nationals at Mets: Sept. 2-3

The Mets could do without another meeting with their former All-Star second baseman Daniel Murphy, who signed with the rival Nationals during the offseason. The NL East-leading Nats have won nine of 13 against the Mets this year, and Murphy in particular has inflicted quite a bit of the damage, batting .423/.446/.885 with seven homers in just 13 games. By the beginning of September last season, the Mets had already overtaken the Nationals and were well on their way to winning the division. If they're to make the same surge this year, we could be in store for playoff baseball early.

Red Sox at Yankees: Sept. 27-29

David Ortiz at Yankee Stadium: What's more must-see than that? Barring an unforeseen change of circumstances, this will be Ortiz's final visit to the Bronx, an environment where the Red Sox legend has thrived in and where the spotlight is suited for his larger-than-life presence. Ortiz has mashed 31 homers in 114 games split between the two Yankee stadiums, but no taters will mean more to the retiring legend than going deep in one last showdown with his famed rivals as the Red Sox look to punch their ticket to the playoffs.

Blue Jays at Red Sox: Sept. 30-Oct. 2

The Big Papi farewell tour continues and ends in Boston, where Ortiz will play in front of the Fenway faithful in the final regular-season series of his career. There will be tributes and ceremonies, and potentially playoff berths at stake. The storylines will be plentiful, too, with the backdrop of Edwin Encarnacion's free agency looming over the Blue Jays (and Fenway Park), and David Price trying to secure a spot in October at the expense of his former team. With the two clubs currently sitting neck-and-neck in the AL East race, this series could shape up to be the most anticipated showdown of the season.