The 26-year-old has been limited to just three appearances in all competitions this season having seen his campaign placed on hold when a blood clot was discovered in his calf back in November.
MacDonald was placed on a course of medication spanning four months in a bid to clear up the problem with a return to action planned for March, but Adkins has now confirmed that the centre-back will remain with the medical team for the remainder of 2018/19.
“We won’t see Angus this season,” Adkins said at his pre-match press conference ahead of Saturday’s trip to Brentford. “Hopefully we’ll get him back for pre-season.
“He’s stayed with the medical team. We were hoping for him to be back by March but that’s not going to happen now. All being well we’ll get him back for the pre-season period.
“It’s tough for him. He’s only played three games for us this season. We need to get to the bottom of it and help him through the situation.
“We’ve got good medical staff and we’re dealing with it. Medically we’ve got to get it right and that’s what the club are doing. We’ve got to allow that process to happen and support Angus as much as possible.”