He has come through the lower leagues in Germany, 4th and 3rd division, after being let go as a 16 year old by Werder Bremen. I think coming up that way shows good character, and helps develop it. I think we will see him involved in most match day squads.
Lallana mentioned in this interview in January, about 1.30 in, a tough time for Undav in his personal life, he was emotional after scoring against Boro. https://www.brightonandhovealbion.com/my-albion-tv/videos/3013509/lallana-great-to-have-mac-back/