Kelly endured 12 months on the sidelines after suffering an ACL rupture of his right knee against Manchester United in September 2012.
"For my development and in terms of confidence, it's been fantastic - just what I needed," said Kelly to liverpoolfc.com.
"It's been the bridge before coming back to the first team. It's much more difficult going straight back into the Premier League or the Carling Cup than reserve level.
"I've played a few games and I'm so glad that the reserve team have had me playing there. The manager has been fantastic playing me at centre-half and giving me a chance to play right-back.
"To be able to get those runs up and down [the wing] again has been vital to my rehabilitation."