The injury, and his year-long struggle to regain full fitness, forced Smith to reconsider his best position, and his Manchester United future.
He is now fighting for the central defensive midfield role at Newcastle and the run-out at Stamford Bridge came after losing his place to new signing Cheik Tiote at the weekend.
Smith told the Daily Mail: "I've not been the same player since my injury. Eduardo had the same injury and he struggled so much and the thing is you've got to make the best of it.
"I've changed my position and I'm still trying to learn that and it's good for me, it's interesting.
"Every game and every week is definitely a bonus because it would have been so easy to pack it in or not fight hard enough to get back in and so easy to let your standards drop.
"It takes hours of work, hopefully Antonio Valencia will be able to get back to the level that he was at before. I know it will be very difficult but I'd like to wish him all the best."