Dylan Hartley could be suspended from the Lions tour after he was sent off during the Aviva Premiership final.
The Northampton captain was dismissed on the brink of half-time at Twickenham, amid claims that he swore at referee Wayne Barnes following his decision to award Leicester a penalty.
If the hooker is suspended, it may open the door for Ireland's Rory Best to take his place on the tour.
Hartley had been warned about his language by Barnes just two minutes before he was sent off.
Barnes had told him: "Please keep your comments to yourself or I may have to deal with it. Do not talk to me like that."
The penalty for verbal abuse of a match official ranges between six and 18 weeks. If Hartley is found guilty that would surely end his hopes of touring with the Lions.
Leicester ran out 37-17 winners.
"Please keep your comments to yourself or I may have to deal with it. Do not talk to me like that" - Wayne Barnes to Hartley
Warren Gatland's squad depart for Hong Kong and the first fixture of their ten-match tour on Monday.
Northampton assistant coach Dorian West told ESPN at half-time: "I don't really know what's been said out there.
"I know Wayne had a word with Dylan before that. We will have to listen to the ref mic and see what's been said.
"Dylan is obviously very disappointed and feels hard done to. He insists he was talking to his player."
West was critical of Leicester director of rugby Richard Cockerill, who was furious earlier in an eventful first-half when Courtney Lawes was not yellow carded for a tackle on Toby Flood.
"We've had a few problems. Richard Cockerill has been intimidating officials all through the half. It's embarrassing but that's where we are. We are up against it now."
A spokesman for the Lions told PA Sport that if Hartley receives a suspension which was to rule him out of the second match of the tour, against Western Force on 5 June, then he would be replaced in the squad.
"The coaches and the team regather tomorrow. There will be an assessment of the situation and it is out of our hands," the spokesman said.
"Warren Gatland has always indicated that these players (competing in Premiership and PRO12 finals) would not play in the first match against the Barbarians but they would have to be available for the second match of the tour.
"That is the criteria for Hartley coming on tour. If he gets a suspension that prevents him from making that second game then that is where we are."