Never seen him in my games, so judging on my own savegames he wont become a great striker. Ive checked some save games to look him up, and he isnt that great. At first sight he seems like a decent striker (given he is 15), but seeing as your Man City I would not recommend getting him seeing from this screen (he simply wont be good enough). If you are really looking for a good young striker I would recommend players like Mitrovic/Fierro/Benzia/Lukaku , given they are somewhat older. But they will be way better for a team like City on the long run.