Mijnans has emerged as one of the standout attacking midfielders in the Netherlands after a prolific season with AZ.
The 26-year-old scored 21 goals and registered nine assists in 50 appearances across all competitions during the campaign.
Noordhollands Dagblad reports Borussia Dortmund have identified Mijnans as a possible replacement for Brandt, who is widely expected to leave Signal Iduna Park.
Bayer Leverkusen are also believed to be tracking the Dutchman’s progress.
Mijnans joined AZ from Sparta Rotterdam in 2023 and remains under contract until 2028.
The midfielder has now acknowledged growing interest from abroad while hinting Germany or Italy would suit his style best.
“It’s still very early,” Mijnans said.
“I think I would fit best in the German or Italian league.”
Dortmund are expected to reshape parts of their squad this summer following another campaign of transition under Niko Kovac.
Replacing Brandt’s creativity and attacking output has become a priority internally, particularly with the Germany international's exit now settled.
Mijnans has built a reputation for intelligent movement, late runs into the box and strong technical quality in possession. His versatility across attacking midfield positions is also understood to appeal to Dortmund’s recruitment staff.
AZ are unlikely to let him leave cheaply given both his contract situation and production this season. But the growing interest from Germany suggests Mijnans could now be approaching the biggest move of his career.