Drenthe is right in doing so, he didnt had his normal salary in 4months now. He had 2 times half of his salary and is still waiting for the other 2 months to get payed. I would do the exact same thing in this situation.
If we are paying for most of his wages, then try to bring him back, at least for the next 6 months, we need a striker who knows Calcio, and who is better than Trezegoal??!!! nobody for the time being, at least in this mercato,