Realistically, no. Not even close.
Yaya alone will not hinder the team. We've been without Aguero, fernandinho, Nastasic, to name a few for the majority of the season.
Yes Yaya is a monster of a player but with Aguero back it will give us a boost.
Milner has played the holding role in Yaya's place before and done a phenomenal job and I can see him taking Yaya's place as he's been played in a holding role most of the season.
Look at Liverpool. They just lost Henderson for 3 games and Sturidge's loss isn't certain. Henderson has started every single game this year and Sturridge has clearly been an integral part of their scoring. The game against Chelsea will be the one that decides the title. If They win then I think Liverpool takes it.