Now Schrenk is pitching coach for the Gulf Coast League Phillies, one of the team's rookie-level affiliates. He has kids the same age as the teenagers he, manager Roly DeArmas and coach Kevin Jordan are working with. The organization has placed several of its top choices from this year's First-Year Player Draft in the GCL including right-handers Shane Watson and Mitch Gueller (both compensatory first-round selections), outfielder Dylan Cozens (second round), infielder Zach Green (third) and outfielder Andrew Pullin (fifth).
All were playing in high school just a few weeks ago. None have turned 19 yet. All figure to learn a lot about baseball -- and life -- in the next few months.
The Phils' front office loves their upside. And the baseball people are even more excited that, under the new rules, all were signed in time to begin their professional careers this summer. That's a big contrast to top prospects Roman Quinn, Larry Greene and Mitch Walding, who all came out of high school a summer ago, but agreed to terms too late to play last season.
The Phillies have been taking it slowly with Watson and Gueller, since neither had pitched in a while when they reported.
"We want to make sure they're ready before we put them in a game," assistant general manager of player personnel Benny Looper explained.
Schrenk likes what he's seen so far, though.
"They're both real eager to want to get better and learn. They're coming out and doing their early work, their balance stuff in the gym. They both look like they have really good arms," he said. "They're young. They need work. They're going to have to take their lumps, like they all do down here. But I like having the young kids and having something to work with."
"We think Cozens has a lot of power potential," Looper said. "If you see him in batting practice, he's a big strong kid. He just needs to go out and get at-bats, like all these young guys. Pullin is a baseball player. He's got good tools. We worked him out at second base prior to the Draft, and we're playing him in the outfield right now. But we'll also work him into games at second to see where his future is. Green is a shortstop and he'll play there some, but it looks he'd be more a third baseman. So we'll see how that plays out."
DeArmas is out early every morning with Green, hitting him ground balls. But there are more than baseball adjustments to be made.
"I think the big thing is that for most of them, it's their first time away from home," the manager said. "Of course, they miss the girlfriends. You can see them getting down about that and having problems there. Just getting into their routines for pro ball. I think that's the biggest thing. You know, coming to the ballpark every day, fundamentals, BP, weightlifting and all the stuff like that."
The Phillies do what they can. The team provides their meals, so nutrition shouldn't be an issue. All the players are required to live in the same motel, and if they have a problem, Schrenk is right there. He's staying there, too.
"I'm right there. I'm a knock on the door away or a phone call away. And you see them running around there, so it's kind of nice," he said. "It's kind of like a dorm, that kind of atmosphere. They get fed, so it's kind of a college type of atmosphere a little bit, but they know they're here to do a job.
"We'll see what they do, and it's going to be hot down here. I've got to make sure they have sun screen, I've got to make sure they drink enough water, get their rest at night. There are a lot of things that go into it besides just pitching."
And, yes, Schrenk will occasionally conduct bed checks.
"Kids are going to make mistakes. That's part of our job as coaches, to make sure they stay on track," he said. "But I think it's neat because I have kids the same age as these kids. And I tell them right up front, 'I'm going to treat you the same way I treat my son. If you're going to mess up, I'm going to get on you. And if you do good, I'm going to be there to pat you on the butt.'"
Another adjustment is that few players have cars. Several have addressed that by buying bikes.
"I just kind of hang out in the hotel and go eat. Take a nap, walk some places," Gueller said. "I bought a bike, so now I can ride around and have a little more freedom than just walking. There's not a whole lot around, but this is kind of the life. Being in the clubhouse and at the ballpark, other than that, just kind of unwind and relax, hang out. Some guys have Xboxes, so you can go play video games."
Said Watson: "I went to Georgia a couple months ago for about two weeks. It wasn't too bad, but nothing like leaving home and living on my own. It's pretty different. It's hard to explain, but it feels pretty good to be doing my own thing, working hard."
Green, who played in summer leagues the previous two summers, is one of the few who has been on his own. But even for him, this is a different experience.
"Because of the fact that it's a job. You've got to dress nice all the time. You've got to look the part. I'd say that's the biggest thing, you know it's every day and it's a job you have to take care of," he said.
Cozens said he's gotten used to being away from home.
"It's cool. It's tough in the beginning to get used to it, but now it's a lot of fun," he said.
For Pullin, it's all about the baseball.
"I love it, playing baseball every day. It's a dream," he said.
For the Phillies, it's pleasant to dream about how good each of these players might be when they grow up.
Paul Hagen is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.