Ghana defender Baba Rahman will remain at Chelsea for the rest of the season after failing to secure transfer on Championship deadline day.
The transfer window for the English Championship ended on Friday at 11 GMT-1.
Chelsea were hoping to send the Ghana left-back on another loan deal after Middlesbrough and Watford expressed interest in having him for the season.
Following discussions between Chelsea and the two clubs, Boro appeared to be serious in snapping up the defender on transfer deadline day.
However, a last-minute hitch meant that the move could not go through.
He is expected to get some minutes in the Chelsea development squad to stay fit and target a move in the winter.
The 26-year-old left back, who joined the Blues from Augsburg in the summer of 2015, has made 15 Premier League appearances since his move to England
Rahman has since enjoyed loan spells at Schalke 04, Reims and Real Mallorca.
His career has been hampered in recent years by a cruciate ligament rupture, which kept him out of action for more than seven months in 2017, and a knee injury, which sidelined him for virtually the whole of last season.