Dustin Ackley’s month in Tacoma, where he hit .365, did nothing to help his major league career, as the Mariners hoped it would. / Drew Sellers, Sportspress Northwest

The Mariners completed the first half with a feel-good flourish: their first sweep of the season, their first three-game winning streak since May 1-4, and the kind of offensive production Eric Wedge needs to extend his own career in Seattle – 48 runs and 11 homers during a seven-game home stand that transformed his team from ennui-inducing to interesting.

Even first baseman Justin Smoak, a season-long study in flailing, stirred to life with five extra-base hits, a three-hit game and a four-RBI outburst against Boston and Los Angeles. A tease whose numbers to date suggest a journeyman rather than All-Star career, Smoak is now hitting .272  — .386 in July — with eight home runs after batting .240 with three long balls in the season’s first two months.

Almost lost amid Smoak’s current resurgence, Raul Ibanez’s 24 home runs and the potential Nick Franklin, Mike Zunino and Brad Miller have exhibited in recent weeks is Dustin Ackley’s contrasting plight.

While the Mariners produced 18 runs on 29 hits, six of them homers, against the Angels, Ackley went 2-for-11 (.181) in the series. In the midst of Seattle’s 78 hits and 48 runs against the Red Sox and Angels, Ackley went 3-for-17 (.176). Only one hit went for extra bases and he drew two walks.

In nine July contests, Ackley is 8-for-37 (.216) with two RBIs. His on-base percentage in those games: .293. His OPS: .590. Remarkably, .590, grim as it is, represents a dramatic uptick. When the Mariners farmed Ackley to AAA Tacoma eight weeks ago, he hit .138 with a .443 OPS in 19 previous games.

The Mariners sent out the No. 2 overall pick in the 2009 amateur draft following a May 26 game against Texas. Recognizing he was over-matched in the majors, the Mariners did so hoping he would solve his plate issues while gaining a much-needed shot of confidence. They even moved him from second base to the outfield, giving him kind of a re-start to his career.

The plan seemed to work. In 25 games, Ackley hit .365 with 10 extra-base hits, 14 RBIs and a .972 OPS. Deeming him ready, the Mariners summoned him home June 26. What they have discovered is that the cure didn’t take and Ackley is no more equipped to handle major league pitching now than he was.

Ackley left for Tacoma with a .205 batting average. Fifteen games and 44 major league at-bats into his return, Ackley is still hitting .205.

Although 25, Ackley has been in steady decay since his rookie year when he hit .273 with a .766 OPS. After showing such promise, Ackley appeared to have bottomed out in 2012 when he hit .226 with a .622 OPS. But that, as we’ve seen, was a false bottom. Two-fold question: How much lower will he go, and is there any upside?

First the nadir: Take all the position players selected in the first round of June amateur drafts over the past decade. Use 1,000 at-bats as the minimum. Ackley, with 1,140 ABs in 1,263 plate appearances, has the lowest career OPS of any of those players, as the chart shows:

Imagine what Ackley’s numbers would be now without that rookie season. Maybe only Ray Oyler, the greatest hitless wonder in Seattle’s professional baseball history, knows.

Drafted a year before Ackley, 11^th overall by the Texas Rangers, Smoak is also on the list. He’s trended up the past month – 1.119 OPS in July following a. 888 June – but has an established pattern of quickly diving the other way if a cloud passes by or he sleeps wrong. Smoak is 26, just hitting his prime. Maybe these dramatic fluctuations are always what we’ll see out of Smoak. Obviously, we’ll see.

Same goes for Ackley, whom the Mariners rushed to the big leagues because they are in perpetual urgency every year and make hasty moves not in the best long-term interests of player or team. The effect of the club’s rush job on Ackley is only now becoming apparent: He is amid the worst OPS season in franchise history by anyone not named Mario Mendoza.

The following chart is based on 350 season at-bats. Ackley has 200 and should easily reach 350 unless the Mariners ship him back to Tacoma Not likely. If Ackley’s OPS doesn’t budge much for the better, only Mendoza will have produced a poorer season, and that’s saying something when the likes of Jeff Cirillo, Casey Kotchman and Chone Figgins, to cite three, are considered.

One plus for Ackley is his youth. Many hitters, Ibanez serving as Exhibit A, don’t mature into solid, every-day major leaguers until much later. Ibanez didn’t blossom fully until 30. A corresponding negative is that Ackley isn’t a natural on the order of Ken Griffey Jr., Alex Rodriguez or Mike Trout, 21 years old and taken in the same draft class as Ackley.

Another negative: Ackley seems to intellectualize his at-bats rather than adopting Griffey’s “see ball, hit ball” approach, the result being that he appears more intent on not making an out than attacking the pitcher. Ackley is what he is: a defensive hitter who allows pitchers to control his plate appearances.

Lest you doubt, on counts without a strike — 0-0, 1-0, 2-0, 3-0 — Ackley has only five hits all year, going 5-for-40, .125. Point of comparison: on the same counts, Trout, four years younger, is 26-for-70, .371, including 10-for-11 on 2-and-0.

Additional minor league seasoning at this point, as his recent stay in Tacoma showed, won’t rectify this. What’s required is that something inside Ackley’s head change fundamentally, which seems unlikely. Tweaking his mechanics or altering his batting stance (been there, done that) and hoping water becomes wine only amounts to show over substance.

It’s difficult to watch a young player disintegrate. But perhaps Ackley, like so many others, was never meant to ascend.