That is according to ESPN FC pundit and former Liverpool full-back Steve Nicol.
De Gea is said to have rejected a final contract offer from Manchester United.
The Spaniard is wanting a big wage increase to around £350,000-a-week.
De Gea’s current deal expires at the end of next season and he could therefore leave the club for free if he does not agree an extension.
So United may choose to cash in on the 28-year-old this summer.
Atletico Madrid stopper Oblak has been linked with a move to Old Trafford.
The Slovenian has been a key man for Atletico since Thibaut Courtois left the club in 2014.
However, Nicol still believes David De Gea is a better goalkeeper than Oblak, despite making a series of mistakes towards the end of this season.
So he cannot understand why United would trigger Oblak’s release clause instead of giving De Gea the wages he wants to sign a new deal.
“His buyout clause is €120m I believe,” Nicol said of Oblak.
“Please help me if I’m mixed up somewhere along the line, they have a goalkeeper that’s actually better than Oblak.
“The only stumbling block it seems to me is that De Gea wants more money.
“So you’re not going to give De Gea more money but you’re then going to splash out €120m?
“I’m sorry, it doesn’t make any sense, not at all.”
Oblak has made 199 appearances in all competitions for Atletico since joining from Benfica five years ago.