Pique and Mathieu are our 1st and 2nd choice currently, it seems.
Vermaelen and Mascherano are behind them.
Bartra is behind them.
Bartra is a squad player currently.
If he will perform well when he will play in upcoming Seasons, he will become a 1st, 2nd or 3rd choice in 2-3-4 Seasons when Mathieu will be gone, and when Masch won't be a priority anymore.
He will be 25-26-27 then and he will still have 7-8 Seasons on top level infront of him, if he will "deserve" his chance.
Bartra fans don't need to panic. He is "only" 23 years old.
Currently he is only a squad/rotation player.
And the next 2-3 Seasons will decide whether he will become a starter one day or he will forever be just a back up.
He doesn't have to be a starter today, it is not the end of the world.
Coaches think that he is not good enough yet to be a starter, but that he still has a lot of potential.
He will get chances and minutes in upcoming Season and the time will tell what will happen with his status in Barca.
His situation is ok, he gets a lot of chances.
Montoya's chances in Barca are, on the other hand, much weaker. The coaches seem to have much less faith in him.