Just prior to the 13th-minute mark during the second quarter of the match at RSEA Park, May arrived narrowly late to a marking contest that Butler was parked under, with the premiership Demon's late spoil attempt striking Butler high.
The Saint was left on the ground for a moment holding his head before getting back on his feet and taking a set shot after a free-kick was paid.
With Butler able to continue to play out the match, the severity of May's contact on Butler would likely see the impact grading fall under 'low'.
Should the match review also assess the incident as careless conduct and high contact, May will likely come away with a fine for the match.
In the chance the match review grade the level of impact as 'medium', May will be handed a one-game suspension if the conduct and contact views remain the same.
The match review's findings are expected to be confirmed as early as Saturday evening.
The former Gold Coast captain missed just two matches last year, one through concussion protocols and a second due to a club-imposed ban.
May was suspended for his side's Round 13 clash against Collingwood after the key defender breached club guidelines for drinking while returning from a concussion injury.
Melbourne claimed a 105-46 win over St Kilda after the opening four periods of Friday's practice match.
The Demons will continue their pre-season run against Richmond next week at Casey Fields.