The Yankees enter the season's second half tomorrow with a 31/2 game lead over the Rays in the AL East. As division leads at the All-Star break go, that's pretty solid.

However, the division race remains wide open with 74 games to go. The Yankees (48-40) are just 61/2 games in front of the last-place Red Sox, with the Orioles (four behind) and Blue Jays (41/2 behind) firmly in the mix.

Here's a look at what the Yankees, who host the Mariners tomorrow, will have to do in order to survive baseball's most balanced division and secure their first postseason berth since 2012.

Stay off the DL

This may seem obvious, but it's a more pronounced need on a team with as many aging veterans and injury-plagued contributors as this bunch. Masahiro Tanaka, Jacoby Ellsbury, Andrew Miller and Carlos Beltran highlight the 12 Yankees who have been placed on the disabled list since Opening Day -- not to mention the players who began the year injured.

The fact that the Yankees have remained contenders amid so many ailments is a testament to their depth. But with five players on the active roster age 34 or older, their health bears watching more than most.

A-Rod's renaissance

Alex Rodriguez don't need no stinkin' All-Star nod to validate the success of his half-season. His slash line (.278/.382/.515) and run production (18 home runs, 51 RBIs) are evidence of just how important the full-time DH has been, even after sitting all of last season due to a league-imposed suspension.

A-Rod will turn 40 in 11 days, so a dip in his numbers should be both expected and tolerated. However, a full-bore slump during the second half could mean trouble for the AL East hopes.

Take out the competition

Exactly halfway though their slate of matchups against division foes, the Yankees are just 21-17. That's solid, it but could be better. The best way to ensure a division crown is by squashing their rivals.

Easier said than done. The only AL club that scores more runs than the Yankees is Toronto. Tampa Bay pitchers, led by Cy Young candidate Chris Archer, top the division with a combined 3.56 ERA. Baltimore is balanced in both areas, plus the O's lead the AL in fielding percentage. Boston looks the most ready to fall off the pace, but the 2013 champions are hard to count out completely.

The Yankees cannot afford complacency against such competition and an emphasis on crushing AL East opponents will go a long way.