Chelsea are free to sign players in January after their transfer ban was halved by the Court of Arbitration for Sport (CAS) on Friday.
The Premier League side were barred from signing new players for two successive windows by FIFA in February as punishment for breaching rules relating to the international transfer and registration of players under the age of 18.
Chelsea's appeal to FIFA was partially upheld, with the club allowed to register players under the age of 16 but still not permitted to bring in new senior players.
However, Frank Lampard will now be able to add to his young squad next month after CAS reduced the ban to one window, which Chelsea have already served, while halving the 600,000 Swiss francs (£4,500) fine they were handed to CHF300,000 (£2,250).
CAS' sole arbitrator deemed Chelsea had only committed one third of the violations found by FIFA, while the breaches of other rules around transfers were deemed less serious than those attributed to the club by the governing body.
Despite his inability to recruit players before the season, Lampard has overseen an excellent start to his tenure at Stamford Bridge.
Chelsea are fourth in the Premier League, having claimed nine wins from their opening 15 games. The Blues are 14 points adrift of leaders Liverpool but are well on track to qualify for the Champions League.
Lampard's men are third in Group H in this season's Champions League but will qualify if they beat Lille on Tuesday.