The Slovenia international is regarded as one of the best goalkeepers in the world having made rapid progress since arriving in the Spanish capital in 2014 from Benfica.
His current deal with Atletico is set to expire in 2021, and according to Simeone, the wheels are in motion in regards to extending those terms, per Jamie Smith of Goal.
"I know the club is working in order to make Jan stay," he said. "We talked with him this week and he knows what he wants and needs. He knows that we need him too; he's a key player in the present and in the future of the club's potential growth."
As noted by Smith, both Liverpool and Chelsea were linked with Oblak in the summer, although they ended up signing Alisson Becker and Kepa Arrizabalaga, respectively, for world-record transfer fees for goalkeepers.
It was also reported by Isaac Suarez of Marca recently that the 25-year-old was looking to leave the club in the January transfer window.
Having tied down their key forward Antoine Griezmann to a long-term contract in the summer, it'd be a huge boost for Atletico if they were able to get Oblak to commit before the end of the campaign too.
While Griezmann is the man the team looks toward in the attacking third, Oblak has proved himself to be something of a talisman at the base of the team too:
Per Dermot Corrigan of ESPN FC, only recently the goalkeeper made a brilliant stop against Athletic Bilbao with Atletico 1-0 down; Simeone's side went on to win the game 3-2 in dramatic fashion:
Oblak does benefit from having exceptional defenders ahead of him in the form of Diego Godin, Stefan Savic and Jose Maria Gimenez, but the authority with which the goalkeeper operates seems to breath extra confidence into the rest of the team.
While his shot-stopping ability is incredible, there are other facets to his game too. In terms of distribution, he may not rival the likes of Alisson or Manchester City stopper Ederson, but he is sharp off his line and unshakeable in his dominance of the penalty area.
Here's a look at some of his best moments in an Atletico shirt:
Oblak won his first major piece of silverware with Atletico last season in the UEFA Europa League and will want to challenge for more prizes in years to come. If he follows Griezmann's example, there will be strong foundations in place for them to do so.
Atletico will be keen to get this over the line quickly too. Per Suarez, Oblak has a €100 million (£88 million) release clause in his contract, and for a footballer of his ability, some high-profile clubs may be tempted to meet that in one of the upcoming windows.