Ander Herrera has told Mundo Deportivo he doesn't know if he will renew his contract at Manchester United.
In November, the club triggered a one-year extension in his existing deal that will keep him at United until 2019.
The midfielder said he started negotiations with United about a new contract but, for now, his future is up in the air.
"I'm going to fulfill the year I've got left but I don't know if I will renew," the 28-year-old said. "We have started talks but nothing is decided yet."
Herrera said earlier this month that he would like to remain with United as long as possible, having joined the club from Athletic Bilbao in summer 2014.
"I'm privileged because I dedicate myself to what I dreamed of when I was very young," he said. "I enjoy coming each day to the changing room, going out to train, seeing stadiums full of people and having a photograph taken with fans that wait for us at Carrington."
Herrera was instrumental in winning the League Cup and Europa League last season as he made 50 appearances in all competitions, was named man of the match in the Europa League final against Ajax and won United's Player of the Year award.
But he has been forced to accept a reduced role this season primarily because of Nemanja Matic's arrival from Chelsea last summer.
"Obviously, you are happier when you play, but I am also comforted by being physically well, training to the maximum and going home with the knowledge that I've given my all," he said.
Herrera said that while he considers Barcelona's Sergio Busquets to be the greatest midfielder in the world, Matic is among the best, so he has had to adapt to a different role at United.
"What I like is to give solutions to the coach," he said. "I'm a team player and I want to be a part wherever. ... I even played at right back last season against Everton at Old Trafford."
Herrera was handed his first Premier League start since January in the 3-2 derby win over Manchester City and played his part in the comeback, setting up Paul Pogba to score his first goal.
But he was also involved in controversy after the game when video surfaced of him appearing to spit on a Manchester City crest as he walked down the tunnel.
Herrera, however, has maintained his innocence.
"It's ridiculous to think that I would do something like that deliberately," he said. "I didn't even know that I had spat. I then looked at the images and I saw that I did.
"I know where the idea to find the guilty one comes from in order to put the focus of attention on that issue and not on the fact that we had turned around the derby."