Flanagan made his return to first team action last season, and feels his knee is in good shape following a lengthy spell on the sidelines that came to an end in January.
Liverpool manager Juergen Klopp celebrates with Jon Flanagan
Flanagan made a total of nine first team appearances in the second half of last season as he was eased back into action as he tried to work up his fitness to a good level.
Liverpool's Jon Flanagan in action with Watford's Jose Jurado
The defender has been one of three players who has suffered from knee injuries recently who returned to pre-season training early, with Danny Ings and Joe Gomez - who both suffered from ACL injuries last season - have been trying to build up their fitness.
Flanagan told the Liverpool Echo: “It was great to get back in the second half of last season but I wasn’t 100% match fit after so long out.
“Although it was frustrating for me not to be in the squad on matchdays towards the end of last season, looking back now maybe it was the right decision. Now I feel great and things are going well.
“The knee is perfect. I haven’t missed a single session so far and it’s all good. Hopefully it carries on like that.”
Liverpool's Jon Flanagan in action with West Ham's Enner Valencia
It's welcome news for Liverpool, especially in terms of having a local player in the side, but also someone who can provide some adequate competition or cover for Nathaniel Clyne going into the new season.
Flanagan has a good opportunity to push for his place in the side given he will have a full pre-season while Clyne will return to the side late because of his commitments with England's Euro 2016 campaign.
The defender was handed a new three-year deal last season, so Jurgen Klopp clearly feels he has a role to play. It's an important season for Flanagan in terms of his career, and he will be hoping to get a good pre-season under his belt, then a decent amount of first team action in the season ahead.
Manchester City's David Silva in action with Liverpool's Jon Flanagan and Kolo Toure