Chasen Shreve was very good last season. And then he was very bad. For the first four and a half months of the season he was truly outstanding, giving Joe Girardi a very good fourth option in the bullpen. Then it all fell apart in the middle of the August. Shreve allowed ten runs on 21 hits (five homers!) and 14 walks in his final 12.2 innings of 2015. Yuck.
There is no shortage of theories why Shreve struggled so much late in the season. He was fatigued. The league caught up to him.