The Scottish forward was a late withdrawal for Saturday's goalless draw with Charlton due to a sickness bug and remains a doubt.
McLeish said: "We're hopeful we'll have big Garry available again but we'll have to wait and see."
Lee Carsley serves the second game of a three-match ban for his dismissal against Wolves, meaning Damien Johnson should continue in the centre of midfield.
McLeish was impressed with Johnson's display at The Valley, and said: "I knew at some stage he would play a part. With Carsley's suspension I had no hesitation in bringing him in and he showed his battling qualities in the middle of the park."
Sebastian Larsson came off against the Addicks due to tiredness but he should be in contention.
Plymouth Argyle manager Paul Sturrock is expected to keep faith with a winning line-up.
Sturrock was forced to make one change to his starting line-up for the 4-0 win over Coventry.
Chris Barker was recalled after on-loan Manchester United central defender Craig Cathcart suffered a knee injury during the 1-0 win at Blackpool.
Scorers Ashley Barnes, Jamie Mackie and Alan Judge were all substituted during the second half of Saturday's victory to keep them fresh for Monday's match.
Sporting Life