It keeps getting worse for Jay Bruce

Before the eighth inning Tuesday night, there was some intrigue surrounding what the Mets might do with Jay Bruce if the “mental break” prescribed to cure him failed to work its magic against the Braves.

Then Eric Campbell appeared in the on-deck circle.

You read that correctly. After Bruce’s three failed at-bats, Terry Collins didn’t hesitate to replace him with Campbell — a .158 hitter in 37 games for the Mets this season — against the lefty reliever Ian Krol. And in a development that should embolden Collins further, Campbell delivered an RBI single, instantly matching Bruce’s output from his past 11 games.

“It’s one of the worst things you can do as a manager,” Collins said after the Mets’ 5-4 loss to the Braves. “Pinch hit for a star player. But it’s my job.”

Collins had nothing to apologize for. Bruce has had ample opportunity to prove himself, to show he’s worthy of regular playing time, but he’s stubbornly refused to reward the manager’s faith. The only thing left in his favor was the law of averages, which dictates anyone going this badly, and possessing his type of run-producing resume, was bound to turn it around at some point.

Maybe it would have happened in that eighth inning against Krol. But Collins wasn’t willing to find out. After prepping Bruce about the possibility, the manager did in fact pull him for Campbell, and Bruce said it was the first time in his nine-year career that he was lifted for a pinch-hitter.

“It’s very difficult,” Bruce said. “I always think I’m the best choice. But he’s the manager and I respect his decision. It is what it is. I don’t deserve an explanation from the manager.”

Like anyone needs an explanation. The Mets, who have a wild card to win, can’t keep using a hitter who makes an out nearly every time he steps to the plate. Whatever Michael Conforto did to alienate his bosses, he still can do better than that, and it’s not like the Mets have the luxury of time to let Bruce figure things out.

The Mets have 11 games left, and after what we’ve seen from him in the previous 11, does it make sense to double-down on Bruce in the hope that he somehow regains his Cincy powers? He’s hitting .077 (3-for-38) with zero extra-base hits and one RBI over that period. It’s a small sample size, sure. But can the Mets really afford to let Bruce continue on that downward trajectory. Not unless Collins wants to keep pulling him in the late innings, in high-leverage situations.

“It’s not fun to do,” Collins said.

In giving Bruce two days off to clear his head, Collins pushed the last button available to a manager when it comes to dealing with proven, veteran players. Collins used the same technique with Neil Walker before a herniated disc abruptly ended the second baseman’s career season.

Walker took a seat for two days, returned on July 26 and then batted .426 (40-for-94) with seven home runs and a 1.183 OPS over the next 24 games before the back condition did him in. The rejuvenated Walker made Collins optimistic it also might work for Bruce, but there is a notable difference between the two case studies. Walker already had achieved a degree of success in a Mets’ uniform, so he had that confidence to build on. Bruce does not, and that makes us wonder if he’s too far gone to revive at this point.

Collins mentioned how Bruce teamed with perennial MVP candidate Joey Votto to form a lethal combo for the Reds — and that’s what the Mets envisioned for him and Yoenis Cespedes in Flushing. The Aug. 1 trade, minutes before the deadline, was supposed to insert Bruce in the cleanup spot, right behind Cespedes. But Tuesday night, Bruce was dropped to sixth, with Curtis Granderson hitting fourth and T.J. Rivera, the 27-year-old rookie second baseman, batting directly above him.

That already had to be humbling for Bruce, who had 25 homers and 80 RBIs in 97 games with the Reds before being shipped to Citi Field, a place where the boos are rapidly increasing in volume. And now it appears Bruce is powerless to stop them — unless he stays in the dugout.

By David Lennon

dave.lennon@newsday.comDPLennon

David Lennon is an award-winning columnist, a voter for baseball's Hall of Fame and has covered six no-hitters, including two perfect games.