The promotions came a day after Indianapolis' season closed, as it was eliminated from the International League playoffs by the Durham Bulls on Saturday. The Pirates plan to use all of the players that they called up in the remaining weeks of the season, especially Glasnow, who will be moved into the starting rotation on Wednesday.
Glasnow was sent down on June 10 amidst considerable struggles. He posted a 7.45 ERA and a 1.91 WHIP over 12 starts in the Majors this year. He recorded just three quality starts. He then proceeded to excel in Triple-A, however, going 9-2, 1.93 ERA in 15 starts.
"It was at the point where I went down and it was like nothing else, it's the worst it can get right now," Glasnow said. "I was up here, I didn't do very well, so it was the time to make a big change, and it was kind of like the perfect time for it. It clicked my first start in the Minor Leagues and I carried it on through, so I'm just looking to do the same thing here.
"Just kind of a whole change of mechanics and switched everything up, and fastball [velocity] went up," Glasnow added about what he improved in Indianapolis. "I had two offspeed pitches, so it's a lot easier to pitch with three pitches than half of one. … I'm excited to ... continue to do that and keep getting hitters out."
The Pirates placed Harrison on the DL with a fractured left hand that ended his season.
Manager Clint Hurdle pointed out that the Pirates are especially looking to get assistance from Runzler and the newly acquired Leathersich, who was claimed off waivers from the Cubs on Sept. 4, as attacking left-handed hitters late in games has been an area of inconsistency.
In addition to getting a good look at relievers Santana and Barbato, the Pirates are also looking forward to seeing more from the lone position player called up.
"[Stallings has] done a very good job for us when called upon catching. ... He's been productive behind the plate, he's been productive with the bat," Hurdle said. "All of these guys are going to get opportunities for us to take a little peek behind the curtains of what they may provide for us going into next season."
Alaina Getzenberg is a reporter for MLB.com based in St. Louis and covered the Pirates on Sunday. This story was not subject to the approval of Major League Baseball or its clubs.