The 21 year old midfielder is on a free transfer after leaving Dutch Club Willem II, who Town play tonight (Monday), with Kolsi going straight into the squad to face his former employers.
Marko spent the last part of the most recent campaign out on loan but has six U21 caps to his name and has played for his Country from U17 upwards.
Kolsi will train with Town on their three game tour of Holland and Belgium that starts tonight and will be given a chance to shine in the arranged games.
Kolsi on week trial
Magilton is taking three trialists on the tour with him; Alexis Bertin, Indridi Sigurdsson and now Marko Kolsi. Frenchman Bertin has already played in the Blues first two friendlies and impressed in a holding midfield role.