The Polish centre-back, who can also operate in the middle of the park, left Tynecastle to join Greek club Panionios in January of this year.
However, he made only one substitute appearance and was released at the end of the season.
On the look-out for a new club, he’s been given the chance to win a deal with Derek McInnes’ side and posted a picture of himself on Imgur in an Aberdeen training top.
Signed by Robbie Neilson in the summer of 2016, Nowak didn’t actually feature for Hearts until Ian Cathro took charge of the club.
After Cathro’s sacking he played twice under interim coach Jon Daly but featured only once more following Craig Levein’s hiring as the next permanent manager.