MLB

Yankees vs. A’s: Who’s David and who’s Goliath?

SEATTLE — Every fifth day, the Yankees have the weapon to fight a nuclear war. On the other four days, their battles often resemble bayonets against Scud missiles.

So with Masahiro Tanaka not available to pitch until Tuesday, the Yankees open a three-game series Friday night against the well-rounded A’s in Oakland’s O.co Coliseum, a dump of a ballpark disguised as a sewage plant.

The A’s, who own the best record in the American League at 40-26, will throw Sonny Gray, Scott Kazmir and Jesse Chavez. The Yankees will counter with the slumping David Phelps (0-4 in his last four starts), a somewhat resurgent Hiroki Kuroda and Vidal Nuno, who has been more fortunate than good.

Of course, the biggest disadvantage the Yankees will have is their bats against the A’s arms. And the A’s bats against the Yankees’ starters give them an edge, too.

The A’s were first among AL teams with a 2.83 ERA and their starters are on top at 2.98 and with a .230 batting average against. The lineup is first in runs (5.09 per game) and third in OPS (.744).

After a six-run outburst Thursday night, when they finished a three-game sweep of the Mariners, the Yankees are 11th in runs (4.03) and 11th in OPS (.697). Before Thursday, the Yankees had scored just 32 runs in the previous 12 games.

“The baseball season is like a roller coaster ride, it takes you in a lot of different directions,’’ GM Brian Cashman said Thursday. “It goes up, down, right, left and in circles. Some guys are underperforming and some guys are coming back from injury. You have to work through it all.’’

When Tanaka starts, the Yankees (34-31) are 11-2, so it’s easy to see why he has evolved into the staff ace. However, he can’t pitch every day and can’t hit.

On the plus side, Jacoby Ellsbury has a 16-game hitting streak, Brett Gardner has been consistent, Mark Teixeira is finding his power stroke and Derek Jeter went 7-for-12 with two stolen bases in the Mariners series.

Yet Brian McCann is at .226. Carlos Beltran is 4-for-26 with nine Ks since returning from the DL. Brian Roberts is in a 5-for-32 funk, and Alfonso Soriano’s cold bat (one homer since May 17) only plays against lefties. And the darling of the first two months, Yangervis Solarte, is in a 4-for-24 slide.

Based on the Yankees’ inability to score runs, it figures to be a tough three days in the Bay Area.