Manchester United turned down Chelsea's offer of including Romeo Lavia or Christopher Nkunku as part of the deal that saw Alejandro Garnacho head to Stamford Bridge this summer, sources have told ESPN.
Garnacho, 21, signed for Chelsea in a £40 million ($52.62m) deal on Aug. 30 after falling out of favour under United head coach Ruben Amorim.
United spent £225m on new signings this summer, adding forwards Matheus Cunha, Bryan Mbeumo and Benjamin Sesko to Amorim's squad before completing a deadline day move for goalkeeper Senne Lammens.
But sources have told ESPN that despite an acknowledgement that they need midfield reinforcements, United rejected Chelsea's offer of including Lavia as part of the Garnacho transfer due to concerns over the Belgian's fitness record.
Lavia joined Chelsea from Southampton amid the west London club's spending spree in the summer of 2023 but his game time has been severely limited by injury.
Though impressive when he has been on the pitch, Lavia's repeated muscle issues mean he has missed more than 75 games, making just 31 appearances in all competitions.
He is yet to play a full 90 minutes for Chelsea and is currently sidelined with a quadriceps injury.
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Sources have told ESPN that Nkunku was also offered to United before he ultimately completed a move to AC Milan.
The forward also suffered with injury issues during his time in England and failed to translate the form he had showed for RB Leipzig to the Premier League.
Chelsea travel to face Burnley on Saturday, while United host Everton on Monday.
Information from ESPN's Mark Ogden contributed to this story.