Donaldson regained his spot on the tour thanks to the European Tour order of merit in 2015/16.
He beat Mark Selby and Martin Gould on a run to the last 16 of the 2015 Ruhr Open.
Donaldson also reached the last 16 of the Welsh Open in 2014, winning three matches before Ding Junhui ended his run.
He made the semi-finals of Asian Tour event one in Yixing in 2013, beating the likes of Jamie Burnett and Tian Pengfei before losing to Mark Selby.
Scottish youngster Donaldson made his debut on the professional tour in 2012/13. He earned his place by winning the European Amateur Championship in Latvia.
He comes from Perth, not far from the home of snooker legend Stephen Hendry.