The Swedish striker was United’s top scorer last season with 28 goals in all competitions.
But he suffered a serious knee injury during the Red Devils’ Europe League quarter-final match against Anderlecht at the end of April.
United decided not to renew his contract and he became a free agent during the summer.
But manager Jose Mourinho admitted the club were in discussions with the 35-year-old about returning to Old Trafford for the second half of the new season.
Ibrahimovic has been regularly posting Instagram videos showing his rehabilitation from the horror injury.
And the latest sees him back in the gym doing some heavy rope training before using a medicine ball.
He captioned the video: “No time to rest.”
“Come back soon,” commented on Man Utd fan.
Another added: “Glad to see you back, waiting for the action to begin.”
It comes as three Manchester United stars were slammed for an “embarrassing” dance video ahead of their Premier League opener against West Ham.
