Ruben Loftus-Cheek has joined Fulham on a season-long loan from Chelsea.
The Whites have also bolstered their defence, signings centre-backs Joachim Andersen from Lyon on a season-long loan and Tosin Adarabioyo from Manchester City on a permanent deal.
Adarabioyo, 23, has signed a three-year contract with the option of a further year.
England international Loftus-Cheek will be looking to rediscover his best form, having worked his way back from a ruptured Achilles tendon.
The Blues have looked to thin out a big squad after a prolific summer of spending and have an array of options in central midfield, even after Ross Barkley’s loan departure to Aston Villa.
Loftus-Cheek started Chelsea’s Premier League opener at Brighton, but has since failed to make Frank Lampard’s squad.
Centre-back Andersen, 24, was part of a concerted push by Scott Parker on transfer deadline day to bring in much-needed defensive additions.
Andersen has turned out three times for Lyon this season so should have the match fitness to move straight into Parker’s plans.
The Dane signed for Lyon from Sampdoria for £21.6m at the start of last season, but struggled to hold down his place under coach Rudi Garcia.
He made 18 Ligue 1 appearances last term, but featured in six Champions League matches in Lyon’s march to the semi-finals.
The 6ft 2in youngster made his international debut for Denmark in October 2019.
Adarabioyo has enjoyed successful loan spells with Championship sides West Brom and Blackburn Rovers, where he made 35 appearances last season, scoring three goals.
But the England youth international, who came through City’s academy, has made just three senior appearances for Pep Guardiola’s side.