Agreed - we need to sign two first pick centre mids. I'd only sign Ball if we are very very confident of moving on Gleeson later in the summer.
Last year we started with Tansey, Forrester, Gleeson, Shinnie, Ball, Ferguson and Hoban as options for the midfield 3. Now we have Ferguson, Gleeson and Campbell only.
I'd be happy with Ball and Campbell as 4th and 5th pick in there.