Chelsea will be able to sign players in January after the Court of Arbitration for Sport (CAS) reduced the club's transfer ban.
Chelsea were handed a two-window transfer ban and fined £460,000 ($599,000) in December 2018 after FIFA found them guilty of breaching rules relating to the transfers of 29 players under the age of 18.
The club were found to have breached Article 19 and Article 18b of the Regulation of Transfers and Status of Players by FIFA's Control, Ethics and Disciplinary Committee.
Friday's decision by CAS marked Chelsea's second appeal of the ban after FIFA rejected an earlier attempt to lift the ban and upheld their decision in May, but altered the ruling to allow the club to sign some players younger than 16.
FIFA opened its investigation into Chelsea's academy for potential transfer rule breaches in 2016, when pictures emerged of Bertrand Traore playing against Arsenal in a noncompetitive match as a 16-year-old.
- ESPN Premier League fantasy: Sign up now!
- VAR in the Premier League: Ultimate guide
- When does the transfer window reopen?
- Premier League winter break: All you need to know
The club said they had approval from both the Football Association and Premier League to play Traore in trial games.
Chelsea have shown few signs of being affected by the transfer ban this season under the leadership of Frank Lampard, who took over last summer, leading to academy graduates including Tammy Abraham, Mason Mount and Fikayo Tomori taking leading roles in the side.