Liverpool striker Daniel Sturridge is ramping up his recovery from hip surgery after posting a video online of him training alone at the club's Melwood training ground.

The striker underwent surgery in May having missed the whole of the Reds' pre-season schedule and he has been ruled out for the start of the new campaign to continue his rehabilitation.

ESPN understands the England international could return for Liverpool in time for the crunch Premier League visit to Manchester United on 12 September. And those reports have coincided with Sturridge updating supporters regarding his current fitness with a video posted via his Instagram account of the 25-year-old working intensely away from the main first-team group, along with the message "Closer".

Manager Brendan Rodgers had initially stated Sturridge would return to full training in September, where he would be involved in contact work ahead of a return to the Liverpool team. The former Manchester City and Chelsea forward has endured an injury-ravaged 12 months and made just seven Premier League starts last term with a long-term thigh complaint, an absence that contributed to Liverpool's failure to qualify for the Champions League.

Sturridge has also suffered from hamstring problems during his Anfield career and while he has been a success during his two-and-a-half years on Merseyside, his career threatens to be overshadowed by fitness concerns.

Closer ...

A video posted by Daniel Sturridge - Dstudge (@danielsturridge) on

The absence of Sturridge is one of three injury worries facing Liverpool before the start of the season, with Joe Allen and Jon Flanagan both out with respective hamstring and knee problems. With the striker out of action, new signing Christian Benteke will lead the line and Rodgers says his side must adapt to the Belgium international.

"The key for us and how we work when we don't have the ball is the ability to be aggressive and press, and you can see Christian has that," he said after his debut against Swindon Town, according to the Liverpool Echo. "And the key to playing with the ball is about technique and intelligence and you won't see too many better goals than that in terms of technique. Let's hope he scores some better ones, and plenty of them!

"His hold-up play brings others into the game and his pace is always a threat in behind. For me, he is absolutely perfect about how we work. I know people have questioned is he going to fit into the fluency of how we want to work. But I think he'll show the capacity to do that and also add something to our game, which is that real aerial threat in the box."