The Partick Thistle star has yet to play a competitive clash this season after picking up an ankle knock in the friendly clash with AEL Limassol at Firhill.
After appearing in a couple of Under-20 matches for the Jags' second string, the former Rangers and Dunfermline defender was edging closer to a first-team outing.
His progress was halted ahead of Thistle's 1-1 draw with Kilmarnock on Saturday, however.
And the 24-year-old is determined to bide his time and only push for a starting berth when he is fully geared up for a return to action.
McMillan said: "I had a setback in training the other day.
"I have had an ankle problem and it has swollen up again.
"I don't want to rush things.
"I haven't played yet so I just want to get it right so that I can come in and hit the ground running.
"I am just playing it by ear just now. I am feeling fit and I just need to make sure that my ankle is not swelling up before I come back and get involved in games.
"I came here to play in the top flight. I am looking forward to getting on the board.
"The gaffer has been great. He is a young manager learning the game and he has been great with me with the injuries and me coming here, that was part of the reason I came here."