The Colombian forward was suspended for Saturday’s 4-0 win over Ross County and was not part of the Rangers party that travelled to Eindhoven earlier in the week to secure group-stage Champions League football by defeating PSV.
Van Bronckhorst has installed Colak as his No 1 striker, a summer signing from PAOK, and the Croatian scored twice to continue his rich vein of form to compensate for Morelos’ absence.
"I think we reached a really high level today,” said Van Bronckhorst of the victory at Ibrox that moved the club top of the cinch Premiership until at least Sunday afternoon. “I was really pleased with the performance, pleased with the clean sheet. The goals we scored were of a really high level.
"I’m happy with Antonio, I think he is in a really good moment right now. We just have to keep pushing him and getting the performances that we want.
"In terms of Alfredo, he worked hard this week. We will sit down this week and speak about him and his future, but as I said before, he is still our player, he knows what he has to do to become available for matches again. In this first week, the reaction that he has shown has been very positive.”