The Newcastle star and once Newcastle star must be driving the club's hierarchy insane.
The striker hadn't scored while on loan for the Magpies - so why place that burden on the side on a full-time basis?
At the same time, Newcastle's interest in Siem de Jong seemed to make sense. A goalscorer and a leader at Ajax, Luuk's older brother looked perfect for the Tyneside outfit.
But just look at Newcastle now. You couldn't make it up.
How unlucky have the Magpies been to have seen Siem suffer a recurrence of a collapsed lung - as well as a long-term knee injury earlier this term - while brother Luuk has scored 10 league goals in the Eredivisie this season!?
Last night, the 24-year-old even netted a hat-trick...
The older De Jong may yet play a crucial rule at Newcastle in the years to come but to see the man who looked so awkward in front of goal last campaign net freely as Holland's fifth-top scorer must be infuriating for the club's scouts.
Granted, Luuk looked good with his hold up play last term and succeeded in pretty much most areas outside of hitting the back of the net. But he never scored - and that's not good enough for a striker.
In a perfect world, both would be at St James' Park and both would be netting clinically. This, though, isn't the perfect world. It's the world where most things seem to go wrong for the Magpies...