United have endured a miserable campaign and currently sit 13th in the Premier League.
Their struggles have continued under Ruben Amorim, who replaced Erik ten Hag in November, with the Red Devils winning just four of their 14 league matches since his arrival.
Despite spending around 180 million pounds last summer on Joshua Zirkzee, Noussair Mazraoui, Matthijs de Ligt, Leny Yoro, and Manuel Ugarte, United were unable to strengthen significantly in January, only signing Patrick Dorgu from Lecce.
According to Spanish outlet Fichajes, United are now planning a squad overhaul and could cash in on Garnacho to fund a deal for Balde.
The Spanish international is seen as a key target for Amorim, who wants to reinforce the left-back position despite Dorgu's recent arrival.
Garnacho has made an impact off the bench but has struggled to secure a regular starting role.
While Amorim is said to appreciate the Argentine's talent, United's financial constraints and defensive needs could force them to sacrifice the winger.
Barcelona are reluctant to let Balde leave, reportedly valuing him at around 50 million euros.
However, United could raise funds through Garnacho's sale, with Napoli and Chelsea already showing interest in the 19-year-old in January.
Nigeria international Samuel Chukwueze has expressed his excitement at rediscovering top form at Fulham, crediting manager Marco Silva for playing a crucial role in his resurgence.
Leeds completed a stunning comeback from 2-0 down to snatch a 3-3 draw against a reeling Liverpool and pile fresh misery on Arne Slot.
Manchester City secured a second successive Premier League victory at home against Sunderland, Chelsea were held scoreless away to Bournemouth while Tottenham managed to beat Brentford.
Aston Villa delivered a major jolt to the Premier League title race as Emiliano Buendía struck deep into stoppage time to seal a 2-1 win over Arsenal on Saturday.
