The Spanish central midfielder has only played 146 minutes since arriving from Atletico Madrid in September.
If the club were to decide on Saul today, they would reject the chance to make his deal permanent.
The midfielder will have to prove his worth when he does get a chance to start in Thomas Tuchel's team in the coming weeks and months.
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!