Hefner last started on September 8, but was sent to the bullpen and replaced in the rotation by Jenrry Mejia.
Last week, Terry Collins said Jeurys Familia would get the start on Wednesday. However, Collins said he will keep Familia in a relief role for the remainder of the season due to how effective he's been in that role.
Hefner is 2-5 with a 5.24 ERA in ten games as a starter.
Starting Hefner over Familia is the right call. If the organization ultimately sees Familia (and Jenrry Mejia for that matter) as a reliever, then he should pitch in that role, and not be jockeyed in and out of the rotation. Consistency is important in one's development regardless of the position. In the case of Mejia, his role has not exactly been consistent in recent seasons, and I strongly question whether or not he has been permanently hindered as a result.