High-A Everett transferred Macko from the 7-day injured list to the 60-day IL on July 23 while he continues to deal with an unspecified injury.
The Mariners haven't acknowledged the nature of Macko's injury, but he hasn't pitched for Everett since May 21 and is without a clear timeline for a return. Before hitting the shelf, the 21-year-old lefty turned in a 3.99 ERA, 1.39 WHIP and 60:20 K:BB over 38.1 innings.