The defender joined Everton last season from Burnley in a £25m move, but endured a frustrating debut season at Goodison Park, with an injury shortly after the club not helping his attempts to settle in.
However, he has started this season in fine form, leading to England boss Gareth Southgate handing him a recall to the squad for the recent games against the USA and Croatia.
Now, Silva has revealed that a series of one-to-one meetings were the key to helping Keane re-find his confidence and return to his best form.
"One of the most important things in football, apart from quality, is confidence," Silva said ahead of Saturday's game against Cardiff.
"If you do not have confidence in your job, not just in football, and you do not have confidence in what you are doing it is normal you do not perform well and show your quality. It is easy for me to understand and maybe for all watching how Michael is different now.
"The decisions he takes on the pitch, his confidence in challenges. The Michael who started in pre-season is different, the confidence has come.
"He is learning every day. That is why I am saying (now) he is a different player. The national coach feels the same way and that is why he picked him."