The former Manchester United winger was left in a heap during a practice game following a hefty challenge from the Manchester City midfielder.
Belgium kick off their World Cup campaign in their first Group G against Panama on Monday before taking on Tunisa five days later. "I do not mind if something like that happens".
Januzaj and De Bruyne stand over the ball.
Januzaj, who now plays his club football for Real Sociedad after leaving United in 2017, appeared fully recovered by Friday when Simon Mignolet posted a photograph to Twitter showing seven members of the Belgium squad posing playfully.
Belgium head coach Martinez also didn't mind the challenge.
Speaking in a press conference, he said: "In a natural way, it shows you that it matters".
The ex-Wigan boss is liking the intensity.
"You don't want to hurt anyone".
Januzaj was able to continue the session and insisted afterwards that De Bruyne's mentality was because of the "intensity" of training.
The snap included the logo of "Belgium's Got Talent" and Mignolet captioned it with: "We nailed the first audition today!"
Martinez has words with Januzaj.
Belgium are now preparing for their World Cup opener against Panama on Monday.
How will Belgium fare at the World Cup?