"There are times when I am at home and Max is in Monaco and I've thought 'Damn, it's really nice what has happened to him', but for years - day and night - we did everything together.
"And then he left suddenly," Jos Verstappen told the Dutch newspaper De Telegraaf. "It's a natural process, I know that, but when we entered motor sport together, I didn't think it would go so fast," he added.
"I miss him. It's that simple."
However, Jos admits it is also "nice" to have more time for himself, but is also not ruling out returning to the fray with another promising young talent.
"I do think about it," said the Dutchman. "I've even talked about it with Helmut Marko, who knows that I have a lot of contacts in the lower racing classes."