The Portuguese forward recently joined Rio Ave on loan but insists that a successful return to form can improve his bid for a regular place in the first team at Old Trafford.
"Sir Alex advised me to leave and find a club where I could play more often, so that I could make a great return in the future," he told reporters.
"Obviously something went wrong in the last phase of my career. I had a serious injury which thankfully I have fully recovered well from.
"I'm fine physically now. I was always training and playing. It's good to come here and I want to show what I can do."
Bebe has never started a Premier League game for United.