But Roberts is expected to make his return for the Blues this weekend against Newport Gwent Dragons, ensuring he has plenty of time to prove his fitness ahead of Wales' autumn internationals against Samoa, Argentina, New Zealand and Australia.
"It has been tough missing a Heineken Cup quarter-final against Leinster and the three summer Tests against Australia," said Roberts.
"It has been hard sitting them out but it has made me hungrier to come back and I have worked hard with the physios and conditioning staff."
Roberts will not walk straight back into the Wales team and faces stiff competition from Jonathan Davies and Scott Williams, who started in midfield in the first Test against Australia, before Ashley Beck threw his hat into the ring.
But for the time being all Roberts wants to do is prove his fitness for the Blues, starting against the Dragons.
"It's a place that holds many fond memories for me," said Roberts
"As a kid growing up, my dad was a big Newport fan and he dragged us down there as kids up until I was about 15.
"They beat us down there last year and we owe them one."