The Lions are playing a scratch Pacifica team on Tuesday, because the original opponents went out of business.
The agreement is that all players have had to play Super Rugby this year; one player in their squad has just moved from France (I think).
The Lions raised the point that he didn't fit the criteria, and he now can't play. It seems quite small-minded of the Lions management to nitpick that for the last match for a bunch of the squad.
They're also bringing in two more players, taking the overall squad size to 44, to prevent the test side "having to play twice in 5 days", according to the BBC. I don't see how that squares with also playing anyone from Saturday on Tuesday as that would be even less time, and they've already split the squad - the first test side will also be the second test side.