"You're going to have starts like that. It doesn't matter what time it comes," Glasnow said in a quiet postgame clubhouse. "You've got to keep your head up and move on."
The Bucs' sixth straight defeat dropped them to eight games under .500, their lowest point since they were eight under on May 20, 2014.
With right-hander Jameson Taillon out indefinitely following surgery for suspected testicular cancer, the Pirates need another young starter to step up behind Gerrit Cole and Ivan Nova. Glasnow showed signs of improvement in his last two starts, providing reason to believe he could be coming into his own as he officially shed the "prospect" label.
He followed up his first Major League win on May 2 by pitching into the seventh inning on Sunday. Everything seemed to be going well in the first two innings Friday night, too.
"I was on time," Glasnow said. "Everything felt good."
The third inning immediately proved to be a different story. Glasnow's fastball flattened out and found too much of the plate. Chris Iannetta led off the inning by crushing a middle-middle fastball off the batter's eye.
"Seemed like everything kind of was heading the wrong way after the home run off the back wall," manager Clint Hurdle said.
After walking pitcher Patrick Corbin, Glasnow served up four straight hits: a triple, a double then consecutive singles. Just like that, the D-backs had four runs before Glasnow could record an out.
"He just couldn't really get anything going. It seemed like whatever he threw up there, they hit hard," catcher Chris Stewart said. "Unfortunately, against a really good lineup, when you miss your locations, they're going to make you pay for it."
Yasmany Tomas grounded into a forceout but reached safely to avoid the double play. Then came the final blow, Brandon Drury's three-run homer on a high, 86.8 mph changeup.
"Glasnow has a really good fastball and curveball," Drury said. "He just left some pitches up. He got in a little trouble and had a bad inning, but he's got good stuff for sure."
Hurdle walked to the mound and took the ball from Glasnow. The rookie remained seated in the dugout as Josh Lindblom finished the inning, alternately staring out at the field and holding his head in his hands. Nights like this one, Stewart said, tend to be tougher for younger pitchers.
"They haven't experienced it before, so they don't know how to deal with it," Stewart said. "Some guys are able to get out of it. It's not like he backed down. It's not like he got afraid. He kept attacking. Just unfortunately attacked a little too much in the zone, and he got hit."
Seven starts into the season, Glasnow has a 7.98 ERA. Even as he struggled in April, the Pirates maintained that it was in everyone's best interest for him to remain in their rotation. They believe there is nothing more Glasnow can learn from dominating Triple-A hitters like he did the past two years.
What can he learn from what went wrong Friday?
"I knew what it was," Glasnow said. "Continue to work and be on time and don't lengthen out, and we'll be good."