The Grand Slam star, Man of the Seires on the Lions' 2009 tour of Sputh Africa, missed last month's tour of Australia due to a persistent knee injury which required surgery.
He was sorely missed Down Under as Wales crashed to a 3-0 series whitewash but is back in training ahead of the new season.
It is a huge 12 months for Roberts, who completes his medical studies in May, with the Lions touring Australia in the summer.
"I have been really impressed with Jamie," said Cardiff Blues director of rugby Phil Davies.
"He's been back in since day one and is working especially hard. Jamie has been outstanding and will, hopefully, be back playing sooner or later.
"We don't know when it's going to be for certain, whether it will be September or October.
"But Jamie has been setting an excellent standard and he will be ready to play for the Blues before the autumn international campaign."
Davies is determined to kick-off life at the Arms Park with a bang and hopes to have his international contingent back as soon as possible.
But he insists he will not rush Roberts back too soon.
"We are hoping our internationals will be involved in the first few games of the season.
"We are working out our plans with the Welsh Rugby Union."