Scottish clubs are poised to be allowed five substitutes per game if they reach the group stage of the Europa League.
All four of the Premiership's representatives are in with a chance of making it to the competition proper, with third round ties taking place this week.
Celtic are in Latvia to take on Riga, and will face Sarajevo or Budocnost Podgorica in the play-off round if they prevail.
Rangers face Willem II then either Galatasaray or Hajduk Split, with Motherwell at home to Viktoria Plzen or SønderjyskE should they beat Hapoel Beer Sheva on Thursday.
Aberdeen, meanwhile, face a coronavirus-hit Sporting in Lisbon as they aim to set up a tie with LASK or Dunajska Streda.
In those ties only three substitutes will be allowed, but Scottish sides could be given two extra changes if they make it to the competition proper.
In the Premiership clubs are permitted to make five changes, provided they do it in only three windows.
And UEFA could take a decision on whether or not to follow the same path when the executive committee meets in Budapest on Thursday.
Juventus president and UEFA executive committee member Andrea Agnelli has backed the move.
He said: "I think we want to make sure that we see this also at international level, in the Champions League, Europa League, so that we have a consistent, harmonised style of play.
"This was a consensus we had across the general assembly when we discussed it amongst ourselves, especially given the congested calendar.
"From October to Christmas, national team players play every three days for three months."
