The Situation: Entering the season, the Marlins were counting on Jose Fernandez to front their rotation. Since he was lost to Tommy John surgery, the team has been trying to piece together a workable rotation, as they sit just 0.5 games out of the second National League Wild Card slot. As they shove left-hander Randy Wolf and right-hander Kevin Slowey to the side, BP’s top-ranked Marlins prospect, Andrew Heaney, gets the call. He will make his MLB debut on Thursday against the division-rival Mets.

Background: The club’s top pick (ninth overall) in 2012, Heaney has blown through the minor leagues, reaching Double- and Triple-A in just his second full season as a professional. Heaney breezed through 12 starts (13 appearances) in the Florida State League in 2013, posting a 0.88 ERA before notching a 2.94 ERA in six Double-A starts to close out the year. He came back this year to lower his Double-A ERA with a 2.35 mark, striking out nearly a batter per inning in 53 2/3 innings of work. The Marlins then promoted him to Triple-A, where he posted a 2.74 ERA and 3-0 record in four starts.

Scouting Report: Working from a classic pitcher’s frame, Heaney mixes a three-pitch arsenal extremely well. His feel for keeping hitters off balance and avoiding patterns has developed rapidly since turning pro, with some of his greatest gains coming early this season. Heaney’s delivery is smooth and repeatable, and the ball comes out of his hand with exceptional ease.

Heaney will routinely sit 91-93 mph with his fastball, dipping to 88-89 at times and ramping it up to 96-97 mph when he needs a little extra. His fastball has natural life and jumps at hitters thanks to his smooth and simple delivery. Everything looks easy for Heaney on the mound, and at times he appears to lull hitters to sleep before unleashing a plus heater.

Heaney’s best secondary pitch is a legitimate plus slider that has some projection remaining. He knows how to throw the pitch for strikes and move it out of the zone as a chase pitch, and even when he doesn’t have his best feel, the pitch can miss bats. At its best, Heaney’s slider can be a wipeout pitch that gives him two offerings that could approach the plus-plus range.

Rounding out his arsenal, Heaney offers an average changeup that is still developing. He was often too firm with the changeup last season but has gained feel and trust for the pitch during the first two months of this campaign. Adding the feel for the changeup was the finishing touch for Heaney, which should allow him to work through MLB lineups multiple times.

With average command of all three pitches and a knack for working the bottom of the strike zone, Heaney has the stuff and ability to locate that will make him at least a no. 3 starter, and possibly as much as a no. 2.

Immediate Big-League Future: With the Marlins lacking other viable options, Heaney will get every chance to settle into the Miami rotation. His command of a high-quality arsenal should lead to immediate success at the major league level. While Heaney may have a few rocky starts throughout the next three or four months, fans should expect him to be one of the club’s better starters immediately. —Mark Anderson

Fantasy Impact: For the last several weeks, it's been Heaney and not the more famous close-to-the-majors names listed as the top pitcher on the Stash List. In fact, even prior to the news breaking, Heaney was set to take over the top spot from Gregory Polanco. The reason for this is simple: Despite the lofty long-term profiles of Archie Bradley, Taijuan Walker, and Noah Syndergaard, Heaney is the most prepared member of that group to return overall fantasy value, and he should do so immediately. And while he’s polished, his upside is considerable, as Mark detailed above.

With the Marlins finally jettisoning Randy Wolf (among others from their active roster), Heaney makes a comfortable debut on Thursday against the Mets at home. With the lack of pitching depth they have at the back end of their rotation, Heaney should have a spot the remainder of the season, barring injury—leaving him approximately 14-16 starts the rest of the way, assuming the Marlins either give him a breather or two during the season or shut him down in mid-September (both are possibilities given that he only threw 123 innings last year). If he gets 90 innings in the majors this year, a realistic expectation for Heaney would be a 3.50 ERA, 1.20 WHIP, 75 strikeouts and a smattering of wins. There's a real chance that Heaney will be the most valuable Marlins' pitcher the rest of the way in fantasy leagues.

In redraft leagues, Heaney should be owned in all but the shallowest formats (think 10-team mixed with limited bench space), and even in those formats, he warrants a heavy watch. I would not hesitate to throw him directly into your lineup in a tasty opening match-up. In NL-only leagues, he beats Bradley and Syndergaard to the punch and will likely go for a few dollars less than he deserves to because some owners will hold out for more upside. I'd be willing to throw $20-24 in that format to get him in hand. In keeper/dynasty formats, Heaney is a must-own everywhere, and someone to use a high-priority waiver claim on (though not the top one—that should go to Javier Baez, Kris Bryant, or Syndergaard). Don't be fooled by his polish; Heaney has the goods and profiles as a no. 2 fantasy starter long term. —Bret Sayre