Such a scenario is foreign territory for Messam, one of Super Rugby's true ironmen. The 31-year-old played more minutes than any other player in the past four campaigns, sitting out only two games in six seasons.
Messam has matched that total already this year but both absences were part of the All Blacks' rest requirements. But it will be a different story in Invercargill, leaving the Chiefs understandably nervous with the playoffs around the corner.
"There are a number of diagnoses he can go through," said assistant coach Tom Coventry. "I don't think it's too serious - I don't think it's going to be a season-ending sort of thing - so we're just hoping that he'll come right in the next short while and be ready for the playoffs.
"He's got a little bit more medical assessment to go. It is frustrating but we try to have the mantra that we just get on with things. It's part of footy and we try not to lament our losses."
That approach has been Chiefs' only choice in recent weeks. Kicking off with Aaron Cruden's season-ending knee injury, Dave Rennie's side have endured a horror run of health, with Brodie Retallick one of four front-line locks to lose significant time and Sonny Bill Williams still out.
Messam and Sam Cane, though, were constants. The loose forward duo are the only Chiefs to play more than 800 minutes this season, while seven Highlanders and six Hurricanes have surpassed that mark.
But the Chiefs have been shorn of their leader at an unwelcome time, with tomorrow's victor in the box seat to lock up second spot in the New Zealand conference and home advantage in the first week of the finals.
The Chiefs will be without six first-choice players for the showdown and there are no guarantees surrounding Messam's return. The blindside flanker is still owed another week off ahead of a busy international campaign, a rest period initially pencilled in for next week's trip to the Reds.
Whether that is still needed remains doubtful. "If we can manage to use that [rest] time with injuries then we will," Coventry said. "It's not ideal because some of the guys are training and working pretty hard on other aspects when they're injured, so it's not actually a freshen-up.
"We'll talk through it with the New Zealand Rugby Union."
Michael Fitzgerald is back to tackle the Highlanders and, with Retallick and Matt Symons again unavailable, he will partner Ross Filipo at lock.
Maama Vaipulu replaces Messam on the side of the scrum, with Cane assuming the captaincy.
In the backline Damian McKenzie shifts to fullback for Tom Marshall (knee) and brother Marty comes in at first five, while Anton Lienert-Brown continues at second five in place of Williams.