I admit to not knowing all that about Lo Celso, but it seems to me that they both occupy the same (useful) position on the pitch. I'm all for rotation and such, but keeping an AM field of Son, Alli, Lamela, Lo Celso, Eriksen and Moura happy (all of which I consider somewhat wasted in deep midfield) is looking a bit City-esque. Seeing, or rather hoping, that we won't have the same injury problems next season - unlikely as we are Spurs after all - having more than two of Winks, Sissoko, DNombele and Dier in treatment at the same time, I doubt there will be the same need for deputizing.
Edit: if so happens, we won't have any excuses for not going hard after one of the cups at least.