De Gea has been nominated for the PFA Team of the Year for every season since the 2015-15 campaign.
But ex-England boss Capello claims he's still not sure about the Spaniard.
"I'm not totally convinced by De Gea," he said on Italian TV.
“He never exits from the goal. He is great in the goal, he has improved with the feet, but he never exits from the goal."