Malacia is training with MLS side FC Cincinnati as he looks to relaunch his career following his release from Old Trafford in the summer.
The 27-year-old Dutchman left United after four years at the club, having managed just 15 minutes of senior football in his final season there.
He is currently on trial with Cincinnati, working with the first-team squad while the club decides whether to offer him a permanent deal.
"FC Cincinnati has a good relationship with Malacia's agent; training with the team is an opportunity for both parties to see if they are a good fit," the club said in a statement.
Malacia joined Manchester United from Feyenoord in 2022 in a Ā£13 million move, but his time at the club was repeatedly disrupted by a serious knee injury that kept him out for 17 months and required two separate surgeries.
He made 50 appearances in total for United, with just 11 of those coming across his final three seasons combined.
He spent part of last year on loan at PSV Eindhoven, making 12 appearances during a brief spell back in the Netherlands, before United confirmed his departure this summer as his contract was allowed to run down.
A move to MLS would mark a fresh start for a player who arrived at Old Trafford with a growing reputation in Dutch football, only to see persistent injury problems derail his time in Manchester almost from the outset. Malacia had been a regular for Feyenoord before his move to England, helping the Rotterdam club to an Eredivisie title before United moved to sign him as competition and eventual cover for Luke Shaw at left-back.
His United career never recovered its early promise. After a solid start, the knee problem that first flared up in 2023 proved difficult to shake off, and he found himself down the pecking order, with academy graduates and further signings pushing him away from first-team plans under successive managers.
Cincinnati's interest comes with the MLS season still in its closing stages, meaning any permanent deal would likely need to wait for the appropriate registration window, but the trial gives both club and player the chance to assess whether a longer-term move across the Atlantic makes sense.