I can't see the catastrophic picture that some posters here portray if we don't sign a midfielder tbh, but maybe because I don't feel that basing your investment choices on absolute worst case scenarios is a rational thing to do. I mean Lemina will probably miss two weeks as Gabon will be kicked out from the quarter finals max, and Asa will miss three weeks, and all those weeks are Champions league free btw. At this point of the season and from what we know (again basing my analysis on facts as much as possible) Marchisio will have 2 months of football in his legs, and Pjanic will be fully integrated into the squad and Khedira will still be our best midfielder, if during those couple of weeks an injury occurs we'll count on Sturaro (criminally bashed and underrated here) and Hernanes may be fielded against a serie a side for a match or worst case scenario in 2..It absolutely isn't the end of the world, and Allegri can always make a tactical change and play with two midfielders or even use Pjaca in the midfield for a match as it was rumored that he sees him in the mezzala role. And if worse comes to worst we can always loan in some stop gap ala Boriello but this time in the midfield.
Don't get me wrong I'll be over the moon if we get a good midfielder and kick Hernanes' ass out of Turin, but if it can't be done we are not doomed and we should be able to achieve our season's objectives which in my opinion are winning the Scudetto and reaching the CL's semi finals and hope for the best at this point. Cheers.