CINCINNATI -- In the first half of the season, Mitch Keller was the guy who set the pace in the Pirates’ rotation, posting numbers that were remarkably similar to his All-Star campaign in 2023. But like in 2023, the second half of his season has been bumpy.

Friday may have been the biggest divet in that unsteady second half, matching his career high with eight earned runs allowed as the Pirates lost the series opener to the Reds at Great American Ball Park, 8-3.

"Just not in the zone,” said Keller of his night. “Just throwing balls and falling behind in the count. They were ready to hit. They were pretty aggressive early too."

Tyler Stephenson was the main culprit early, launching a first-inning homer to open the scoring and then clearing the bases with a three-run double in the third, but the troubles extended beyond him. Keller walked a season-high five hitters and only struck out one, which was a season-low.

Friday was the third time since Aug. 9 that Keller has allowed at least seven earned runs in a start. He’s had a handful of quality starts and even a seven-inning scoreless gem in that two-month stretch, but it’s been eerily similar to how the second-half of 2023 played out, to the point that his season ERA now identically matches his 2023 total: 4.21. He signed a five-year extension this Spring Training to head the rotation for years to come, and while he has been a leader for a young rotation, the on-field results have not been as consistent.

“It's always tough,” Keller said. “You never want to do bad, obviously. So after a tough one, yeah, it sucks. Just nothing I can do about it now. Just got to get back after it tomorrow. It's done, it's over."

Perhaps most concerning is the drop in his velocity. His four-seam fastball averaged 92 mph Friday, 2.4 mph lower than his season average. While all of his offerings were at least one mph lower than their season average, the dip in the four-seamer was the most eye-opening, being his lowest average in a game since Sept. 21, 2021.

Keller said he was not looking at his velocity in the game and that his concern lies with his pitch location and execution. It’s pretty common for pitchers to lose some velo coming into September

“At this point of the season, that can definitely be a factor,” said manager Derek Shelton. “It's something that we'll definitely take a look at."

Keller is in line to make one more start before the season wraps, so he has a chance to at least end his season on a better note.

Friday’s loss was also the 82nd of the season for the Pirates, sealing a sixth straight losing campaign. The group had higher expectations coming into the season and were in the playoff picture at the Trade Deadline, but stumbled from there.

"I mean, it's [lousy],” Keller said. “Nobody wants to lose, nobody wants to be in this position where we're not playing for really anything at the end of the year. Yeah, it just sucks. Obviously we'd want it to be different, but that's not how it's going right now, so we've got to make it be different."

"I think it just shows you how much room we have to get better,” Shelton said. “I think that's the big thing that you have to continue to focus on. Getting better. We're not in that spot right now, and that's our focus as we move forward to the last [eight] games of the season and into the offseason."