It's hard to be a Strikeout Factory when you're not shipping product. Since making a brief appearance in the big leagues and then being sent back down to Triple-A Scranton, Jacob Lindgren underwent surgery in June to remove a bone spur in his elbow. He was done for the season, and we'd have to wait another year for him to return.
There was a time when Lindgren, even among pretty skeptical bloggers and beat writers, was considered to be a possibly huge piece of the bullpen going into 2015. And for good reason, as the reviews were rave: Kiley McDaniel described his wipe-out slider as "hellacious" and Keith Law said he was a good LOOGY at worst and a closer at best.