that is a decent concern, barca needs a striker that makes runs behind or can be a target man type of player.
my hope was that because griezmann has good link play he would actually have a good first touch/layoffs/passes and wouldn't lose the ball like suarez constantly does, so the fact he is a second striker helps in that aspect. he also has the pace to get behind when making a run and ability to actually score his chances. for it to work it would need a good chemistry between him and messi and for him to make runs behind the defence, but maybe that is wishful thinking from me.
It isn't just about link up plays. Suarez awareness for example is amazing. He can play with his back to the goal which can't be said about Griezmann, that makes life way easier for Messi.
Griezmann usually have someone in front of him, Mpabbe,Morata,Giroud,Costa, Torres etc. He will be in a very new position, in new style in new team at the age of 28.
I've no doubts he will score plenty of goals, he will make it look like worth it initially, but when it matters most it will be exposed. Just like Ibra except there won't be clash of egoes
Factor age and price and I hate it.
And I understand I want Felix who is similar player, but he is right footed who is 12 years younger than Messi with potential to learn new tricks and position, good resale value etc. And even then I don't deny it is huge concern