Now he is the leadoff batter for Williamsport of the short-season class-A New York-Penn League and was recently named to the league's all-star game, which is set for Tuesday in Niles, Ohio, home of the Mahoning Valley Scrappers.
Heading into the weekend, the 19-year-old Quinn was batting .275 and had a .353 on- base percentage as the Crosscutters' leadoff hitter. He had 17 stolen bases in 21 attempts and, in another demonstration of his speed, had nine triples.
That's not bad for somebody learning on the job.
"The kid never hit lefthanded and is facing college pitchers in our league, and it is pretty special what he is doing this year," said Williamsport first-year manager Andy Tracy. "He is a game-changer, and when he gets on base we are a different club."
Quinn was the 66th overall selection in the draft and considered the fastest player among Baseball America's top 200. His signing for $775,000 went right down to the deadline as he also had a scholarship offer from Florida State.
Quinn, the Phillies' No. 8 prospect according to rankings by The Inquirer, understands he is a work in progress at the plate and in the field.
"With switch-hitting I am getting more comfortable each game," Quinn said before Monday's 7-1 loss to the visiting Connecticut Tigers. "I've been having my ups and down with it and have to keep with it."
In Monday's game he went 3 for 5 with a double, a standup triple, and an RBI, all batting lefthanded. One of his most impressive plays was a groundout to short, a routine ball that he almost beat out.
"He has the ability to change a game in a number of ways," Phillies director of player development Joe Jordan said. "We see him developing as a switch-hitter and being an offensive threat from both sides."
So far Quinn has been getting plenty of practice hitting lefthanded. Entering the weekend he was 16 for 42 righthanded (.381) and 33 for 136 lefthanded (.243).
It's no surprise he has struggled on defense, having committed 22 errors in 43 games. Yet the Phillies are not concerned. They understand he is playing a new position and errors are part of the learning process.
"The errors are kind of elevated because he gets to a lot of balls he probably shouldn't get to," Tracy said.
Many of his errors have been on throws, Tracy said.
"I am becoming more of a vocal leader out there on the field and starting to make routine plays," Quinn said. "Sometimes I am not as focused at shortstop and make some little mistakes that cause me to make errors."
This is all part of the growing process for somebody who excelled in basketball. A scoring point guard, Quinn averaged 21 points per game as a senior, but he had no illusions of making a career in that sport.
"I had some small junior colleges looking at me, but my size didn't help me," Quinn said.
Quinn has missed time recently with asthma, including games on Wednesday and Thursday. He was seen by a doctor on Friday, and according to a Phillies official was cleared and rejoined Williamsport.
Quinn said he didn't begin really concentrating on baseball until he entered high school. He understands there is so much to learn and remains both humble and hopeful.
"My goal is to keep improving at shortstop and to keep improving my lefthanded swing," he said. "I just want to get better."
Contact Marc Narducci at 856-779-3225, firstname.lastname@example.org or @sjnard on Twitter.