Between age 15 and 21, you need to play atleast 3 seasons at a club to be considered HG for that club by UEFA. Currently we have only Pinsoglio. For Serie A its less strict, you need to be owned for 3 seasons between age 15 and 21 by a club to be HG, but dont necessarily have to play there (can be loaned out or coowned). Thats how Rugani is HG for Serie A but not CL (we owned/coowned him for atleast 3 seasons between age 15 and 21, but he did not play 3 seasons in that timespan for us to be HG in the CL). Kean was, Immobile would be, Mirante, Audero and Romagna also from other Serie A clubs