Goal France claim the two clubs held preliminary talks over the speedy Senegal winger after the first leg at Roazhon Park.
The Gunners scouted the 21-year-old at last summer's World Cup and he has been monitored during the current campaign when his form has been inconsistent.
He was identified as a potential signing by former head of recruitment Sven Mislintat and it seems the Gunners remain interested even after the departure of the German.
But Sarr, who turned the tide of the first leg Rennes' way when he was brought down by Sokratis to earn the defender his second yellow card, did not show up in the return leg at the Emirates Stadium.
The winger looked nervous and a little clumsy when he did get the ball on a night where hardly anyone in the visiting side matched the standards they had set in Brittany, Arsenal winning 3-0 on the night to advance to the quarter-finals 43 on aggregate.