PITTSBURGH -- When they traded six of their veterans before the non-waiver Trade Deadline, the Padres left little doubt that they've begun to embrace a full-fledged youth movement.
That movement was never on display more than during Tuesday's 6-4 loss to the Pirates at PNC Park. In Luis Perdomo's second consecutive start, San Diego fielded a starting lineup featuring six rookies -- the most in the Majors this season. No Padres team had started six rookies since the franchise's inaugural 1969 campaign.
So perhaps Tuesday's mixed bag of results from the youngsters was to be expected. Outfielders Travis Jankowski, Alex Dickerson and Jabari Blash continued to thrive since being given regular playing time. But the Friars weren't without their share of rookie mistakes, which may have ultimately cost them the game.
"The little things get overlooked that guys who have been on the field at the Major League level understand a bit better," said Padres manager Andy Green. "... It's little intricacies of the game that aren't taken care of in the field that kind of put us in a difficult position."
Green got specific, pointing to three pivotal moments in the ballgame.
First, rookie shortstop Jose Rondon came off second base while trying to turn a double play in the second inning. A replay review confirmed as much, and Rondon was charged with an error that would ultimately cost the Padres a run.
"That's Rondon, who has been in the Minor Leagues, where you could swing off that base quickly," Green said. "Now you've got to hold second base. It's thinner margins for error."
In the fifth, second baseman Ryan Schimpf was unable to execute a swipe tag after baserunner Josh Harrison had been caught in a rundown. Harrison was initially called out, but a video review confirmed he avoided Schimpf's glove. (Green once again pointed to the absence of replays at the lower level.)
The biggest blow came later in the frame, when Perdomo left a sinker over the heart of the plate to Gregory Polanco, who crushed it into the last row of the right-center-field seats for a three-run homer.
In an 0-2 count, Green would've preferred that Perdomo continue to pound the bottom of the zone instead of trying to sneak one past Polanco. Green called the pitch, "just not a pitch he's ready to execute at this point in time in his career."
Rondon's error, Schimpf's missed tag and Perdomo's grooved sinker all marked Padres growing pains -- and understandable ones, at that.
But for each of those growing pains, there's reason for optimism. Both Perdomo and Schimpf started slow, before finding a groove when they were given more opportunities. That appears to be what's happening with Blash, who launched a ninth-inning homer off Pirates closer Tony Watson.
In a few sporadic appearances during his first big league stint, Blash batted just .120 with one extra-base hit. When the Padres called him up to replace Matt Kemp last week, they vowed to give him consistent playing time. He's rewarded them with a 1.035 OPS since.
"There's a lot of talent here," said Blash. "We're all going through the same thing, growing together. For us, it's just keep grinding, take as much information as we can from the coaches and hopefully mold into Major League ballplayers."
Although he's only 25, Wil Myers is one of the club's de facto veterans by now, playing in his fourth big league season. He says he's already noticed the benefits of the Padres' decision to give increased playing time to their youngsters.
"Right now, we're building for the future," Myers said. "Any time we can get as many young guys in the lineup, I think it's great. They've done a great job so far."
AJ Cassavell covers the Padres for MLB.com. Follow him on Twitter @ajcassavell. This story was not subject to the approval of Major League Baseball or its clubs.