Aberdeen have taken Polish centre-back Krystian Nowak in on trial as boss Derek McInnes looks to bolster his defence.
Former Hearts defender Nowak, 24, is a free agent having had his contract terminated with Greek top flight side Panionios.
McInnes aims to secure another defender before the Europa League second qualifying round with Burnley on July 28.
Former Polish U21 international Nowak is training at Pittodrie in a bid to secure a deal.
He made 21 starts for Hearts, primarily under Ian Cathro and only one start under his replacement Craig Levein.
Frustrated with the lack of first team game time at Tynecastle he transferred to Panionios in January this year.