To come back from such a serious injury at the age of 36 was a big ask, and he hadn't made much of an impact in the cameo appearances he'd been given before the visit to Aston Gate.

But watching him misplace passes, slice shots and struggle to keep up with the game was painful. He calls himself a lion and struts around with an incredible amount of arrogance, yet here he was looking unable to compete in a game against championship-level opposition.

Up to the hour mark, social media was full of United fans questioning whether he was finished or not -- how getting more playing time only seemed to highlight how far his form has fallen since last season.

However, with United a goal behind, Ibrahimovic stepped up to take a free kick on the edge of the area. Wearing the captain's armband, he pulled rank and sent the likes of Paul Pogba and Daley Blind packing.

The Swede hasn't been famed for his free-kick-taking ability since joining United -- although he did score one in the EFL Cup final last season -- but his powerful low drive was perfect, smashing the ball through the wall and past Luke Steele to level the score for United.

Ibrahimovic didn't last much longer before being substituted, but while his general contribution had been poor, he did more for the team than anyone else, as United went on to concede an embarrassing late winner and drop out of the competition they won last season.

While United supporters who back Ibrahimovic could feel smug after his goal, the game did little to prove that he is capable of making a full recovery, though it didn't conclusively show he's finished either.

Zlatan Ibrahimovic Dan Mullan/Getty Images

Ibrahimovic isn't match fit and has barely played for the best part of the year. One could look at this period as his preseason, where he is trying to find his feet, and when his fitness is better, perhaps we will see the level of performances he was capable of before his injury.

But that will require plenty of playing time, and Jose Mourinho will have to consider whether he can give minutes to a 36-year-old on his way out at the expense of other players and possibly results.

Even if Ibrahimovic can improve his fitness and contribute goals, how much time do United have to spare to help his recovery? If he was at his peak, there'd be no question that the club would have to do all they could to help him get back to his best, but with his one-year contract coming to an end, United can't even guarantee he will be at the club next season.

Romelu Lukaku can't play in the No. 9 role for every game, but Marcus Rashford and Anthony Martial are champing at the bit to be given more playing time in the position.

Mourinho feels a strong loyalty toward Ibrahimovic, but his priority should be to bring through the next generation of United's attack rather than the rehabilitation of a player whose career is almost over.

Rashford and Martial have done well this season in the wide positions, with a total of 30 goals and assists between them, but both see their future playing in a central role. It's understandable that £75m summer signing Lukaku is ahead of them in the pecking order, but it's harder to justify Ibrahimovic being afforded the same treatment.

It's too early to tell definitively either way, but his comeback hasn't been as simple as supporters might have hoped. To be back on the pitch eight months after suffering from an injury that could have ended his career was remarkable -- if anyone could do it, Zlatan could. But getting back to his best might be a task that's too big even for him.

Ibrahimovic gave United a lot last season, so he deserves a chance. But for the sake of United's future, Mourinho can't wait indefinitely for something that might never happen.