Johnson is now targeting a return to the first team for this weekend's home clash with Norwich City.
"It was just fantastic to be back playing again," Johnson told the club's official website.
"Obviously I've been a long time out and it's been a hard few months for me but fingers crossed I'm over all that now.
"The last two injuries were pretty much on the same spot and it's been difficult to try to stay positive. I want to push on from this and we all want to get three points against Norwich."