The 29-year-old, who has won 57 caps for England, admitted he "didn't really give it a thought" when he found out he had not been included in Brian Ashton's 32-man party for the forthcoming tournament.
Having played just a handful of matches for Brive, the French Top 14 club he joined in December, Cohen knows he has to put his international prospects on the backburner while he regains his match fitness.
But the former Northampton Saints wideman, whose 31 tries put him joint second in his country's all-time try-scoring list, is not discounting a return at Test level.
"I wouldn't have picked me, so I am not surprised Brian hasn't," Cohen said.
"I didn't even know the squad was being named, to be honest. It was hardly a shock I wasn't in it, and I didn't really give it a thought.
"I have played only 20 minutes for the Barbarians (against South Africa) and a couple of games here in France. I'm also playing out of position at centre, which I don't mind at all, even though it's not my best position.
"I'm getting back my match fitness, never mind being ready for internationals. I need games under my belt.
"I am not that disappointed. Obviously you always want to be in the squad and I'd like to be involved in the Six Nations, but I've still got a few years left in me yet.
"I'm only 29 so I'm not too concerned. I'm sure if I get back to my level, I'll be back in there."