The midfielder was left out of four matchday squads in the wake of United’s 5-0 defeat at Bolton Wanderers back in March.
The U’s have since played in a 4-3-3 set-up, with a single six in midfield and two creative midfielders pushed higher up the pitch.
McGuane returned to the fold as a substitute in the 5-0 win against Peterborough United last month, and made further starts from the bench against Lincoln City and Exeter City.
The 25-year-old came on for the hurt Tyler Goodrham shortly after the half hour mark as the U’s booked a place at Wembley for the Sky Bet League One play-off final with an aggregate win over Peterborough last night.
Buckingham was unable to give an update on Goodrham, but said of McGuane: “We made a change and he was the ultimate professional in how he managed himself in that time when he was out.
“We said that he’d be very important to us, and he still had a place to play here. We’ve seen how important it was that he continued to be that professional we know him to be.”
Buckingham made a second move at half-time, bringing on Sam Long for Fin Stevens, after the latter had picked up a booking five minutes before the break.
“We took Fin Stevens off at half-time just because we felt that he couldn’t make the challenges he necessarily needed to, and wanted to,” said Buckingham.
“It wasn’t performance-related with him. We’ve got two very good right backs, and it made a lot of sense to make sure we had one that was fresh in the second half and not on a ban, to face a tricky winger.”
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