The Pittsburgh Pirates have plenty of reasons to feel optimistic right now. Their offense is firing on all cylinders—a night-and-day improvement over last season. The starting rotation, anchored by reigning Cy Young winner Paul Skenes, has been solid, and reinforcements are on the way with Jared Jones expected back soon.

But every team has its Achilles' heel, and for the Pirates, it's the bullpen. This was a concern heading into the season, and it's proving to be a lingering issue. The struggles were on full display Friday night at PNC Park, where Pittsburgh squandered a five-run lead and fell 11-9 in 10 innings to the Philadelphia Phillies. The bullpen allowed seven runs (five earned) in just 3.1 innings.

"It's a tough loss," manager Don Kelly said. "Any loss is tough, especially when you have a lead like that."

The trouble started in the seventh inning. Reliever Mason Montgomery took over for starter Braxton Ashcraft and served up a two-run home run on the very first pitch he threw to the red-hot Kyle Schwarber. To his credit, Montgomery bounced back with a scoreless eighth.

Then came the ninth. Gregory Soto, the team's most reliable reliever this season, had a rare off night. He walked a couple of batters and allowed three runs, blowing the save and tying the game. "He has been really good this year for us," Kelly said. "It was a tough inning. Just looked like at times, he lost the plate."

In the 10th, Dennis Santana allowed three runs to cross the plate without recording a single out. The lone bright spot? Brandan Bidois, making just his second career appearance, stranded two runners and got the final three outs of the inning.

Entering Saturday's game, the Pirates' bullpen ERA sits at 4.23, ranking 19th in baseball. The left-handed trio of Soto, Montgomery, and Evan Sisk has been effective overall, but the same can't be said for the rest of the relief corps.

For now, the Pirates are hoping internal improvement can turn things around. But as Friday night showed, the bullpen remains a work in progress.