After being hampered for much of this season by injury, he then missed the FA Cup tie at Macclesfield with flu.
He was also ill in the build-up to Saturday's clash against Leicester and admits: "I felt weak before the Leicester game but I am coming back. I'm used to playing with all my fitness and when I haven't got it, it is hard, but I needed the game to breathe.
"It was a difficult game but I knew it was going to be like that because Leicester are fighting at the bottom.
"We got the three points, though, and I'm happy about that."
As for the speculation regarding strike partner Paolo Di Canio, Fredi says he will accept whatever Paolo himself decides.
"He is free and he has to do what he has to do. I will be happy with him whatever he chooses.
"That is life. Whoever it is that I play with we have to form a partnership and if he left we would have to do it again from the beginning.
"He has not gone yet, so we can't know now, but you can't find the same player - you can't replace him.
"I hope we will both do good things against Chelsea on Sunday - and I hope to score!"