The Miami Marlins have announced the call up of top prospect Andrew Heaney, who will make his major league debut Thursday against the Mets. To make room on the active roster, the Marlins have also designated pitchers Kevin Slowey and Randy Wolf for assignment.
The 23-year-old Heaney has been among baseball's best left-handed pitching prospects since being drafted 9th overall in the 2012 draft out of Oklahoma State University. He owns a career 2.31 ERA in 199 minor league innings, including a 2.47 ERA and 5.27 K/BB in 76.2 innings split between Double-A Jacksonville and Triple-A New Orleans this season.
Both Baseball Prospectus and Baseball America ranked Heaney the 30th best prospect in the game entering this season, as well as the consensus top prospect in the Marlins' system. He is often cited as possessing number two or three starter upside due to his plus fastball and slider combo, as well as an above-average change up, deceptive delivery, and solid command. Along with Fernandez, Nathan Eovaldi, and Henderson Alvarez, Heaney figures to form the core of a potentially devastating Marlins' pitching staff in the next couple of years.
Wolf signed with the Marlins in mid-May after opting out of a deal with the Arizona Diamondbacks, replacing the injured Jose Fernandez. He had been disappointing in six appearances (four starts) for the Marlins, posting a 5.26 ERA (74 ERA+), 4.33 FIP, 3.17 K/BB, and -0.2 WAR in 25.2 innings.
Slowey has been similarly underwhelming this season. In 37.1 innings, the 30-year-old Slowey has a 5.30 ERA (73 ERA+), 2.67 K/BB, and -0.3 WAR, though his 3.73 FIP is significantly better than the raw results would indicate.
In addition to calling up Heaney and designating Slowey and Wolf for assignment, Miami also made a series of other moves Monday, placing outfielder Christian Yelich and catcher Jarrod Saltalamacchia on the 15-day disabled list, while also optioning Donovan Solano to Triple-A New Orleans. Outfielder Jake Marisnick, right-hander Anthony DeSclafani, and first baseman Justin Bour have been recalled to take the aforementioned trio's place on the active roster.
In addition, the Marlins also announced the signing of the number two overall pick in the 2014 draft, Tyler Kolek, to a deal that includes a $6 million signing bonus, the third highest total for a prep pitcher in draft history. The Marlins have now signed each of their top five selections.