The Brazilian winger is valued at Juventus, which never intended to sell him despite Man United's apparent interest.
New Juventus coach Maurizio Sarri vetoed the summer sale of Douglas Costa to Manchester United, according to the Brazilian's agent.
Various injuries plagued the winger during 2018/19, his fitness issues limiting him to just 17 Serie A appearances over the course of the season. The Red Devils looked to capitalize on the 28-year-old's lack of game time by attempting to lure him to Old Trafford, but Juve's incoming manager was adamant he wanted Costa in the squad.
The Copa America champion has featured in both of Sarri's first two league matches as Bianconeri boss, both of which were won by a one-goal margin.
However, he could have been playing in the Premier League instead, with representative Giovanni Branchini telling the Daily Mail: "The interest of Manchester United was strong, a club that has always been interested in [my client].
"It was not the only club, but in England it was certainly the most active team on the trail of Douglas Costa. Juventus never intended to sell him, despite the big pressure from United.
"I sincerely say that [former manager Massimiliano] Allegri and Sarri have never thought of letting him go. [Costa] loves Juventus, but is able to adapt to every reality.
"The Premier League is a beautiful championship, but for now United have failed in all their attempts to convince Juventus to sell him. The player remained in Turin and is a champion."
Having missed out on Serie A star, the Red Devils instead turned their attention to British talent and recruited Harry Maguire, Aaron Wan-Bissaka and Daniel James for a combined fee of approximately £150m.
Nevertheless, Ole Gunnar Solskjaer's men have continued to struggle for consistency, winning just one of their opening four matches in 2019/20.