The 23-year-old has missed the past 11 months with a ruptured anterior cruciate ligament which the right-back suffered in a 2-1 loss to Manchester United at Anfield last season.
The England international captained Liverpool’s Under-21 side to a 4-2 victory over the Red Devils on Sunday night, and Kelly hopes to be back to peak fitness in “six to eight weeks”.
“It was good to get the first 90 minutes under my belt after so long,” Kelly told Liverpool’s website.
“I played last week in a behind closed doors friendly but to get 90 minutes for the U21s was superb for me and my fitness.
“I just want to get as many games in as I can. I missed so much last season and it’s difficult mentally coming back from 11 months out and knowing you
are not where you were last pre-season, because I started the last pre-season flying and that’s where I want to get back to.
“It’s all the hard work that starts now and in the next six to eight weeks I should get back to that fitness.”
Kelly will be targeting a place in Roy Hodgson’s England squad for next summer’s World Cup after being included in the Three Lions manager’s travelling part for Euro 2012.