John McGrath

John McGrath: My trade deadline request, Jack: Leave D.J. Peterson alone

Baseball’s longtime power struggle between pitching and hitting is not much of a struggle these days.

Pitchers rule, sustaining a trend that began a few years ago. As of Tuesday, major-league hitters were averaging .251. Not since 1972, when griping about offensive ineptitude was so commonplace the American League adapted the designated hitter in 1973, has MLB’s collective batting average been so low.

Pitchers, meanwhile, have found the standard-of-excellence bar raised to a level that’s almost unprecedented. When Chicago White Sox left-hander Chris Sale flummoxed the Mariners last week, he improved his record to 8-1 with a 2.16 ERA and a strikeout-to-walk ratio of 96-16.

Those used to be numbers typical of a Cy Young candidate, and yet Sale didn’t even qualify for a spot on the American League All-Star team.

Explanations about the dominance of pitchers range from the hackneyed (a more stringent policy toward the performance-enhancing drugs that spiked home-run production during the Steroid Era) to the obscure (athletes who once developed hitting skills in college — this according to agent Scott Boras, who shared his theory with The New York Times — are turning to football and basketball because MLB’s most recent collective-bargaining agreement has put a cap on signing bonuses for draft picks).

The hitters who’ve remained true to baseball find themselves facing defensive shifts that offer them the opportunity to take the ball the other way — few accept the offer; it’s an affront to their ego. And speaking of egos: Taking a mighty swing, even if the swing misses, is considered less humiliating than choking up on the bat in a modest bid to make contact.

And then there are the pitchers, who throw harder than they did a generation ago because they taller, bigger and stronger. They’re also more prone to take advantage of video and statistical analysis on hitters, who also have access to videos and stats but are always — repeat: always — reacting to the pitcher.

“Good pitching beats good hitting” has survived as an axiom for 150 years. Updated for 2014, the axiom should be: “Good pitching absolutely obliterates not-so-good hitting.”

The dearth of quality hitting throughout baseball has immediate and substantial consequences for the Mariners, whose quest to acquire an impact bat is shared by virtually every other team in contention for a playoff berth. With the nonwaiver trade deadline looming on July 31, general manager Jack Zduriencik will be tempted to make a deal that reinforces the perception the Mariners are in it to win it.

I’m not opposed to the idea of trading top prospects for a veteran capable of upgrading offense prone to struggle against adequate pitching — and prone to disappear against the likes of Chris Sale — as long as the top prospect isn’t a hitter whose name is D.J. Peterson.

The former University of New Mexico star, the Mariners’ first-round choice in the 2013 draft, has obvious potential as trade bait. He hit .303, with 13 homers and 47 RBIs, before a pitch to the jaw abruptly concluded his Single-A season last summer in the Midwest League.

Peterson, 22, returned to rake in the Advanced-A California League — .326, with 18 homers and 73 RBIs — and has continued to pound the ball in Double-A. While the 6-foot-1, 205-pound right-hander might not be physically imposing, his compact swing and shrewd strike-zone judgment qualify him as a rarity: A hard-hitting batter in a sport that’s been overtaken by hard-throwing pitchers.

Peterson isn’t polished enough to contribute to the Mariners this season, and his arrival date in the bigs depends on how well the third baseman copes with an anticipated position change, either to first base or to the outfield. (Seems there’s no place for him at third with the Mariners, as the position is occupied by All-Star Kyle Seager.)

But it’s not unreasonable to see Peterson spending most of next season in Tacoma, and if all goes well — if pitchers stop throwing balls that break his jaw — a big-league debut set for September 2015 sounds about right.

For a team gripped in the day-to-day gruel of a playoff race, 14 months from now seems like something associated with a 24th century space odyssey. It’s not. It’s 14 months.

Think about this: Everything the Mariners covet in an ideally conceived trade — a right-handed power hitter with a contract that won’t reduce him into a rent-a-player on the cusp of free agency — could be realized by exercising some patience with Peterson.

Yes, I know, collegiate accomplishments and superior stats in the low minors don’t necessarily translate into stellar major-league careers. If they did, Justin Smoak and Dustin Ackley would be All-Stars, and the Mariners wouldn’t be groveling for a stick to complement Seager and Robinson Cano in the lineup.

I also know that baseball has changed the past 15 or so years, and that young power hitters now are much more valuable than young power pitchers.

Given the statement the Oakland A’s made over the weekend — the two-time defending AL West champs traded their best prospect for a pair of aces — Jack Zduriencik can’t be blamed for thinking it’s his turn make a corresponding statement.

Go ahead, Jack, use your, uh, magic touch.

Just don’t include D.J. Peterson in any part of the magic act. He’s untouchable.