Chelsea boss Mauricio Pochettino could not guarantee Marc Cucurella's future after their 2-2 draw with Arsenal.
Cucurella impressed on the day, but Pochettino says the club will make a decision on the left-back in January.
He said, "It's a natural process. It was so clear when we arrived here three months ago that some players were in a position where they maybe stay or maybe go.
"I didn't know the past, I can only choose the players that we believe can perform. Marc and the club decide to stay in the last transfer window.
"He is training well, that is why he playing like today, against a very good player like Saka, That is him, he deserves the credit because in the last few months he has worked hard and was able to play on the right side, yes, in this way, only what can happen is the team will be better."