Ability to stop player going on international duty when you have a Champions League final

In my 3rd season with Stade Rennais in France, and my first season in the Champions League, I've managed to get to the Champions League final. I had thought to myself it would be good if we could finish 3rd in the group stage, and then have a good Europa League run. I beat Roma in the playoffs to get into the group stage with player X scoring a penalty away and a hat trick at home. I then managed to beat Real Madrid away to come top of the group, luckily got past Dynamo Kiev, Lyon and Man U (thanks to Jonny Evans and Phil Jones scoring own goals!) and I now find myself in the final against Porto. With my main, top wage earning striker injured, I definitely need player X to step up big for me in the final. Unfortunately, he's been called up by the French Under 21 team to play in the Toulon Festival tournament. I mean, come on. Really? Truth is I absolutely love watching that tournament on Eurosport at the beginning of every summer, but would a player really miss a European Champions League final to go and play there? I think not. What to do? Play a youngster and keep the same system or play another defender/defensive midfielder to man mark their best player?