Panos was one of the biggest defensive European talent before his Leverkusen move, which was recommended to Rudi Völler by his friend and former Greek NT manager, Michael Skibbe.
In his 1st Bundesliga season under Heiko Herrlich (who emphasizes a lot on youth development) he mainly played as an outside CB (mostly LCB but RCB as well) and had some brilliant performances and some not so great ones, but showed great potential overall and was definitely viewed to be a massively successful investment by the board and a very important player by the manager.
His 2nd was crucial for his development and he could've established himself as a starter with his gathered momentum, but he was injured in a bike accident during the pre-season followed by a muscular injury due to rustiness. I wouldn't say he's injury prone, but he's definitely super unlucky.
However, since the appointment of Peter Bosz, who is known for his anti-rotation style and that he isn't a youth type of manager (even managed to chase away 3 of the most talented prospects in his time in Ajax), Panos' playing time was non-existent. He played less than 300 minutes in a year and a half and basically got robbed of valuable formation years.
What you can expect from him:
-An intelligent technical player with good attacking output/sense and huge involvement in the buildup -great passing ability and vision-.
-Versatility, would offer great competition for multiple positions, but you'd prefer him as either a Basham backup or a defensive mid.
-Good direct defensive skills (tackles-duels)
- But a bit of tactical naïvety and an under-developed positional sense, but he is not a stiff player at all and will learn his trade quickly.