The 29-year-old full-back sustained the problem during a cup clash at the Reebok Stadium in February and he has since undergone a period of rehabilitation in America.
Welshman Ricketts admits he is erring on the side of caution as he does not want a repeat of the injury on his return.
He told the club's official website: "It's not just been a case of mending the Achilles and training again. We found I had actually lost my walking technique and I had to learn all over again.
"The trip to the US gave me a couple of ideas about my recovery. The club have been great, so I owe it to them to make sure I do this right.
"It's all a gradual progression but I'm walking well now and it's a case of bringing that into my running.
"There's a lot of work in the pool where the bodyweight is taken off, and I've been working on this machine, like a treadmill, that straps me in and allows me to work at 20 per cent of my bodyweight.
"Of course I want to be back among the lads and out there on the field. I could probably rush things and get back by the start of the season but I'm looking long term. Taking those extra few weeks will be worth it."
Source: Team Talk
Source: Team Talk