The phrase "able replacement" means someone or something that is capable and can effectively substitute or take the place of someone or something else when needed. Full definition
Liverpool look set to appoint Jurgen Klopp as a very able replacement for sacked boss Brendan Rodgers and TuttoMercato claim that the German manager will look to raid his former club Borussia Dortmund in pursuit of defender Neven Subotic. (caughtoffside.com)
Then of course they have a very able replacement in Son if Kane doesn't play! (justarsenal.com)
Klopp is a very able replacement but I would like an Ex player (Adams, Bergkamp, Henry or Vieira to follow suit.) (justarsenal.com)