As noted by blackjackfishtaco in a Fanpost, Gaffney has announced his return to Stanford, where he was a multisport athlete in baseball and football. It's not clear whether he might return to baseball after he completes his stated goal of getting his degree, but he'll miss this season at least.
It's an unfortunate development for the Pirates. Gaffney looked like a nice, late-round find after they took him in round 24. He hit 297/483/441 with State College last summer, posting the same number of walks as strikeouts and showing good speed. His swing was regarded as needing work, but he hit much better as a pro than he did for Stanford in his junior year, so he seemingly was making progress. His OBP at State College was buoyed by a frightening number of HBPs, roughly one every seven and a half plate appearances.