Johnson is equally disappointed with Mykhailo Mudryk, who cost £89m ($109m) to Chelsea after they beat Arsenal to his signature. He has got just two goals and one assist in 14 Premier League appearances which highlights his plight in front of goal.
"Unfortunately, you’d have to say he’s been greatly disappointing when you consider the attributes he’s got. For a player with blistering speed and trickery, he doesn’t seem to use it," Johnson added. "He came for a lot of money, which isn’t his fault, but I definitely thought we’d have seen a hell of a lot more from him. It’s frustrating because it looks as if he has it all, but he doesn’t have the end product at the moment. We were hoping that he would get a couple of goals and kick on, but then he did score a few and he still didn’t kick on. He’s been frustrating overall.”