On Thursday night, the 22-year-old was ranked 29th overall on MLB.com's Top 100 Prospects list.
"I thought he made tremendous strides from the year before," Marlins vice president of player development Marty Scott said. "It seemed like it took a long time before he could rehab and pitch. But he pitched like gangbusters the rest of the year."
The ninth overall pick in the 2012 First-Year Player Draft, Heaney is looking to join Christian Yelich (2010) and Jose Fernandez ('11) as Miami first-round picks positioned to make an impact in the big leagues.
Barring any setbacks, Heaney has an outside chance to win a rotation spot in Spring Training. He has the pure stuff. The question is whether Heaney is completely ready. The more likely situation is the club will give him more time to develop in the Minor Leagues.
"He might surprise some people in Spring Training," Scott said. "Who knows, it's a long shot. Let nature takes its course. But if he makes strides in 2014 like he did last year, I think, at minimum, you're looking at a September callup."
All told, the Marlins placed four players in the annual MLB.com Top 100. Along with Heaney, Miami featured third baseman Colin Moran (51), outfielder Jake Marisnick (65) and lefty Justin Nicolino (81).
The annual ranking of baseball's biggest and brightest young talent is assembled by MLBPipeline.com Draft and prospect experts Jonathan Mayo and Jim Callis, who compile input from industry sources, including scouts and scouting directors. It is based on analysis of players' skill sets, upsides, proximity to the Majors and potential immediate impact to their teams. The list, which is one of several prospect rankings on MLBPipeline.com's Prospect Watch, only includes players with rookie status in 2014.
The Marlins are one of 11 teams with at least four on the prestigious list. And their 178 prospect points also ranks 11th. The defending World Series champion Red Sox feature a league-most nine in the Top 100. The Astros, meanwhile, accumulated the most overall points with 439.
For Heaney, the No. 29 overall ranking comes a week after he was tabbed by MLB.com as the No. 1 left-handed pitching prospect.
In 2013, Heaney made consistent strides. His fastball velocity is on the rise, as he pitched in the 91-94-mph range. The lat injury, which occurred early in Spring Training, caused Heaney to miss significant time. When he was reinstated, he opened at Class A Advanced Jupiter and then was promoted to Double-A Jacksonville.
Heaney combined for a 9-3 record with a 1.60 ERA and a 1.07 WHIP in 95 1/3 innings. The lefty struck out 89 and walked 26.
To make up some innings, Heaney was sent to the Arizona Fall League, where he continued to impress. With an ERA of 1.95 in 27 2/3 innings, Heaney completed his case for being considered the top lefty prospect in the sport.
"He could put the ball where he wanted," Scott said. "He was a pitcher. He wasn't overthrowing. His mechanics were good. The ball was coming out of his hand pretty easy."
The Marlins' top position player prospect is another former first-rounder. Moran was the sixth overall pick in the 2013 First-Year Player Draft. MLB.com recently ranked the 21-year-old fifth on its Top 10 third-base list.
The nephew of B.J. Surhoff, Moran helped lead the University of North Carolina to the College World Series last year.
After signing, Moran started off at Class A Greensboro, where his hitting line was a solid .299/.354/.442. Moran got some additional work in the Arizona Fall League, where he batted .230 with three doubles and 10 RBIs in 87 at-bats.
The Marlins make it clear Moran is their third baseman of the future, but they are in no hurry to rush him. His arrival could be as early as a September callup, but he very well could reach only as high as Jacksonville this year.
Marisnick is another 22-year-old with immense natural talent. The speedy center fielder got a taste of the big leagues last year, and he experienced some growing pains. In 40 games, he hit .183 with one homer and five RBIs.
The day after the season ended, Marisnick underwent surgery to repair a torn meniscus in his left knee. He expects to be at full strength in Spring Training, where he will compete for the center-field job.
Marcell Ozuna enters Spring Training as the favorite at the position. If Ozuna wins the job, Marisnick projects to start the season at Triple-A New Orleans rather than come off the bench in the big leagues.
Nicolino is another promising lefty in Miami's pitching-rich system. The 22-year-old was recently ranked by MLB.com as the seventh-best left-handed pitching prospect. Acquired from the Blue Jays as part of the 2012 mega-deal, Nicolino was 8-4 with a 3.11 ERA in 27 starts last year.
Like Heaney, Nicolino has an outside shot of winning an Opening Day rotation spot. If not, Triple-A could be where he initially winds up.