The on-loan Rangers man replaced James Bolton in Kenny Jackett’s line-up for the 1-0 victory over Lincoln on Tuesday.
McCrorie’s ‘athleticism’ has put him ahead in the pecking order as the Blues boss seeks more attacking thrust from that flank.
Brett Pitman will again be ruled out with a groin injury. He could make his return when Oxford travel to Fratton Park on November 2.
Oli Hawkins (foot) is still at least two weeks away from full fitness.
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Bryn Morris has returned to Fratton Park after he underwent an operation in Germany on Monday to get to the bottom of his abdomen problem.
Jack Whatmough is now back running on the grass as he continues his rehab for his long-term knee injury.
Meanwhile, Rovers will be without top goalscorer Jonson Clarke-Harris.
The prolific striker has netted eight goals in 12 appearances this season but is ruled out with a calf complaint.
Key-man Liam Sercombe was also absent for the Gas’ 2-0 defeat to struggling Bolton on Tuesday and is a doubt.
Former Pompey loanee Tareiq Holmes-Dennis is sidelined with a knee tear and won’t be back until the end of November.
Sam Matthews and Josh Hare are both long-term casualties.