#1 Antoine Griezmann
Numero Uno. Antoine Griezmann needs as many eyes as possible on him tomorrow. It is almost certain from Ernesto Valverde's interview that Lionel Messi won't be rushed back to the team at San Mames.
The San Mames is a dangerous away ground and Barcelona barely escaped the clutches of defeat when they visited there last season. Marc Andre ter Stegen's saves were crucial in the 1-1 draw, which would otherwise have been 2-1 or 3-1.
To win the game, you need to attack, and Barcelona's attack relies heavily on Leo Messi. Since Messi is absent, it has to be someone else, and that could be Antoine Griezmann. In the last preseason game against Napoli, Barcelona's front-three viz. Griezmann, Suarez, and Dembele were on fire.
Barcelona will look to their brilliant squad depth yet again and Griezmann, more than Suarez who is older, and Dembele who still has to improve on his end-product, will be a crucial cog in the team. Griezmann has led the Atleti attack very efficiently, watch out for him in Barcelona's attacking system.