The shirt was emblazoned with "Rashford 9" on the back - a gesture seen as a public show of support for team-mate Marcus Rashford.

Garnacho shared the image while on holiday, and it quickly made waves online. Rashford, who moved to Villa on loan in January after falling out of favour under United manager Ruben Amorim, responded warmly with a comment reading "My brother" followed by a heart emoji.

Sources close to the club have told BBC Sport that Garnacho's post was intended as a gesture of solidarity, rather than a statement on his own future. Nevertheless, the timing and optics of the post have inevitably added fuel to growing speculation about both players' uncertain roles at Old Trafford.

Garnacho, 20, finds himself on increasingly uncertain footing after being told by Amorim in May that he could seek opportunities elsewhere. Tensions between the pair reportedly intensified following United's 1-0 Europa League final defeat to Tottenham, in which Garnacho started on the bench despite playing a significant role throughout the earlier rounds of the competition.

"Up until the final I played every round helping the team, and today I play 20 minutes - I don't know," Garnacho said post-match. "The final will influence (my decision), but the whole season, the situation of the club. I'm going to try to enjoy the summer and see what happens afterwards."

Rashford's future is similarly unresolved. With two years remaining on his United contract, the 27-year-old has been linked with a potential move to Barcelona and has spoken publicly about his admiration for 16-year-old Spanish sensation Lamine Yamal.

"Everyone wants to play with the best. Hopefully - we'll see," Rashford told Spanish content creator Javi Ruiz.

While Garnacho's social media post may have been well-intentioned, the reaction raises important questions for United. Firstly, whether it affects the club's ability to command a strong transfer fee for a player who appears to be angling for a move. Secondly, whether Amorim would consider reintegrating Garnacho into the squad for pre-season, with United set to tour the United States in late July.

Chelsea are believed to be monitoring Garnacho's situation, although their pursuit of Borussia Dortmund winger Jamie Gittens could complicate matters. A return to Atletico Madrid - where Garnacho spent part of his youth career - has also been mentioned as a potential destination.

For now, the message from Garnacho appears to be one of loyalty to his team-mate. But the implications, both in terms of transfer value and dressing room dynamics, may prove more significant in the weeks ahead.

Alejandro Garnacho sparks speculation after wearing Aston Villa shirt