Answer: Brandon Beachy
Beachy looked to be on the way to a promising big league career during the early 2010's. He really established himself during 2011 season, posting a 3.68 ERA and 3.19 FIP in almost 150 IP. He carried that momentum into 2012 and came out the gates hot, sadly an untimely elbow injury cut his breakout season short.
Brandon attempted to work his way back from TJ surgery in 2013 with Atlanta, but sadly he was never the strikeout pitcher he once was. His curveball didn't have the same bite, and his numbers suffered. Beachy's tale just goes to show that successfully coming back from TJ surgery isn't automatic everyone.