The Portuguese star has suffered two long-term injury problems over the last couple of years but is on his way back after six months of rehabilitation following a meniscus injury.
"Without even playing I feel like a better player and a better person because this injury has toughened me up," the 22-year-old told the club's official website.
"I thought that it was tough before but not as tough as it is now. I feel great but I have to wait for the knee as I can't push too hard.
"Hopefully I will get back next season stronger. I'm focusing on that and I'm trying my best."