ATLANTA -- Mitch Keller is in uncharted territory.

Keller is up to 174 2/3 innings after allowing eight runs -- tied for the most he’s allowed in a single game -- across five frames in the Pirates’ 8-2 loss to the Braves on Friday night. He’s never thrown this much in any professional season; with a handful of starts likely remaining, he could flirt with 200 innings. Keller’s velocity has dipped in recent weeks, likely a product of the aforementioned workload.

The 27-year-old has grown exponentially over the last two seasons, but these last several weeks have reminded Keller that there is more growth to be attained. 

“When you’re looking at this for a building thing, I’m trying to build off last year’s innings,” Keller said. “Obviously, we’re not at the point where we’re trying to be … to get to the playoffs, but obviously, the next step of this is trying to find my routine so I can feel good hopefully going into postseason baseball. 

“I’m not saying we’re out of it now, but I’m trying to build for postseason baseball. I think you find out how to get through that in situations like this where I’m at a lot of innings and it is more than I have thrown. If we are going to make the postseason, then I need to throw more innings than I’m ever going to throw.”

Taking on a greater workload is one challenge. Maintaining effectiveness, stuff, while taking on that workload is another. Over the next three-and-a-half weeks, Keller will have to determine what’s needed to pitch successfully as summer transitions to fall. For Keller, pitching successfully, to a degree, requires more velocity.

Coming into play, Keller’s four-seam fastball and sinker clocked in at 95.4 mph and 94.0 mph, respectively. Over his last three starts, the velocity on those two pitches has trended downwards.

On Aug. 25, Keller’s four-seam fastball had an average velocity of 94.3 mph while his sinker had an average velocity of 93.2 mph. 

On Sept. 1, Keller’s four-seam fastball had an average velocity of 94.0 mph while his sinker had an average velocity of 92.6 mph.

On Friday, Keller’s four-seam fastball had an average velocity of 93.6 mph, the slowest the pitch has been in a single game this season. Keller’s sinker had an average velocity of 92.5 mph, which is also the slowest that pitch has been in a single game this season.

Keller’s cutter velocity has dropped in recent outings as well. Following a six-inning, two-run outing against the Twins on Aug. 20, Keller assessed that his cutter performed best when he threw it harder.

The right-hander had a three-start stretch in August where his cutter sat in the low-90s -- 91.4 mph on Aug. 8, 90.7 mph on Aug. 13, 90.2 mph on Aug. 19. Over his last three starts, by contrast, his cutter has been in the high-80s -- 88.7 mph on Aug. 25, 88.9 mph on Sept. 1 and Friday.

Despite the recent dip in velocity, Keller said that he feels great, adding that he thinks, “this is a good learning thing by trying to get over the hump here, look at some mechanical things. I don’t know what it might be, but just try to find something to get the velo back up. [Velocity is] probably the least of my concern.”

Added manager Derek Shelton, “We're in the middle of September, so that's going to be typical, a little bit of a trend down. I don't think that played into it today. I think today, [Atlanta] just did a good job putting the ball in play.”

The Braves put the ball in play, yes, but the quality of contact wasn’t as great as the eight runs against Keller would suggest. Ronald Acuña Jr. and Eddie Rosario had home runs that clocked in at 110.6 mph and 108.4 mph, respectively, but four of the Braves’ eight runs came during a four-run third inning in which they had an average exit velocity of 81.9 mph.

Atlanta’s hitters put eight balls in play against Keller in the third. Of those eight, six were under 90 mph and four were under 80 mph, low exit velocities were a product of well-placed pitches and, in Shelton’s estimation, four broken bats. 

“Yeah, it’s frustrating,” Keller said. “That’s about all I can say about it. I’m making my pitches. I’m doing exactly what I want and giving up soft contact. It’s kind of laughable. There’s nothing else I can do.”

If the Pirates are to make the playoffs in the future, a late-season matchup against a premiere team is a scenario in which Keller must excel. On Friday, Keller did not. He understands what’s required of him for Pittsburgh to play meaningful baseball in October. Time will tell if he can deliver.