On August 1, within an hour of this season’s trade deadline coming to a close, the New York Mets and Cincinnati Reds finalized a trade which sent outfielder Jay Bruce to New York in exchange for prospects Dilson Herrera and Max Wotell. The Mets added Bruce certainly not for his glove, but for his bat, particularly for a little extra thump against right-handed pitching. At the time of the trade, Bruce was having the best season of his career. The 29-year-old right fielder had 25 home runs in just 402 plate appearances, good for a career-best .295 isolated slugging percentage, and a 124 wRC+. After an injury-plagued 2014 and a down 2015, Bruce was driving the ball in the air to the opposite field, had cut down on his strikeouts, and, at the plate, generally looked like the prime version of himself for the first time in several years.

And then, one week ago, on September 20, less than two months after parting ways with a legitimate major-league prospects to acquire Bruce’s bat, Bruce was pinch-hit for in the eighth inning of a close game against the Atlanta Braves by Eric Campbell, he of the career 81 wRC+ which presently rests at 55 this season. Bruce said after the game he had never been pinch-hit for. He certainly couldn’t have ever expected that the first would come for a player with Campbell’s track record.

At the same time, it’s difficult to argue with Mets manager Terry Collins’ lack of faith regarding Bruce. To date, all the Mets have seen from Bruce is a 55 wRC+ — identical to Campbell’s season mark. All they’ve seen is a .188 average, a .262 on-base percentage, and the same ISO as Angel Pagan’s season mark. And so now Bruce has started just three of the Mets’ last nine games, and is being pinch-hit for by Quad-A utility men. Needless to say, arguably the worst extended slump of Bruce’s nine-year career isn’t what anyone had in mind when the trigger was pulled on the trade-deadline deal.

A quick perusal of Bruce’s surface-level numbers don’t reveal all too much being different. The strikeouts are up, but not beyond an extent with which Bruce has succeeded in the past — and besides, the walks are up, too. He’s getting the ball in the air just as often as before, and it’s being pulled as often as before.

What has changed is Bruce has become more aggressive. His already above-average swing rate of 50% is up to 55% with New York, which would rank among the highest figures in the league over the course of a full season. Subsequently, Bruce’s contact rate has dropped from an already below-average 78% to 73%, which would rank among the lowest figures in the league over the course of a full season. Pitchers have responded by throwing Bruce more and more fastballs as the season has gone on, a good indicator of a hitter whose perceived true-talent level has recently changed. More fastballs, more swings, and more misses. It’s the recipe of a hitter who’s pressing in response to being challenged, in turn creating more pressing and more being challenged, and, well, you get the picture.

More specifically, Bruce has once again lost the outer half. And perhaps more troubling, that’s exactly what he’d lost in his two-year slump from 2014 to -15:

When I looked into Bruce’s struggles over the offseason, I’d found that Bruce’s left knee surgery in 2014 led to a change in his swing that resulted in a larger decrease in opposite-field power production than any other hitter in baseball from 2012 and 2013 to 2014 and 2015. Hitting coach Don Long blamed the back leg directly for Bruce’s opposite-field power struggles, saying “[Y]ou try to manufacture the same amount of bat speed and more of that’s coming from your upper half and you’re generating from your upper half, which makes you susceptible to [being quick with the barrel].”

It’s probably irresponsible to speculate on player health, and by all indications Bruce is just fine, physically, but it’s got to be at least somewhat worrisome to see such a relatively recent issue creep back up again. It’s probably worth pointing out, too, that Bruce started off last season in a similarly exciting fashion, only to collapse in the second half to the tune of a 66 wRC+, which is only slightly above his mark to date with the Mets. Bruce doesn’t have to be injured to be fatigued, and maybe he doesn’t even have to be fatigued for bad, old habits to resurface.

But lately, there have been too many at-bats like this one…

… in which opposing pitchers simply pepper Bruce low-and-away with fastballs, at which Bruce flails slowly to no avail. The book seems to be out on Bruce, and until he again begins to do something with these outer-third heaters, he’s got little utility to the Mets, particularly while Michael Conforto continues to do what he’s been doing upon his recall from Triple-A when rosters expanded on September 1.

Since that date, spanning a minuscule sample of 41 plate appearances, Conforto’s ran a 158 wRC+ with more walks than strikeouts and a .226 ISO. And while those 41 plate appearances certainly shouldn’t lead us the conclusion that Conforto is totally fixed from his midseason struggles against breaking and offspeed pitches, they do remind us of what an odd fit the Bruce trade was in the first place. Of course, Conforto was in Triple-A at the time of the deal, his short-term future with the club uncertain, but the point remains that in Conforto and Bruce, the Mets possess two left-handed hitting corner outfielders, Conforto with a projected true-talent wRC+ currently of 106, Bruce at 97. With Yoenis Cespedes and Curtis Granderson rightfully occupying the other two outfield positions, it’s hard to see what Bruce’s role on the team currently is, or has ever been, so long as Conforto exists.

If Bruce is simply a late-inning pinch-hitter, then the Mets paid a pretty steep price for his one plate appearance per game. And when your designated pinch-hitter was recently pinch-hit for with Eric Campbell, well, you don’t exactly have Matt Stairs. On the one hand, Bruce’s struggles since coming to New York are largely mitigated by the fact that they still have Michael Conforto. On the other hand, that very reason for mitigation is a reminder of why the relationship between Jay Bruce and the New York Mets was so puzzling in the first place.