Some former Celtic stars have enjoyed productive spells at Parkhead before embarking on exciting careers elsewhere in the game. Looking at the not-too-distant past, the likes of Moussa Dembele, Kieran Tierney, and venturing further back with Virgil Van Dijk’s success show the pathways that playing for the Hoops can produce for talented individuals. One other former Celtic who has hit the headlines recently is Jeremie Frimpong, who became a Bundesliga champion last weekend, starring for Xabi Alonso’s all-conquering Bayer Leverkusen outfit. During his time in Glasgow, the 23-year-old made 51 app…