When they decide to loan out their existing players, of course they have considered the worst possibilities that they will face, one of which is as you said, being hit by injuries and so on. But we also have to look at it as an option, I mean when the players are in the squad but they don't play, then I think that's not a good thing, especially for the future of the player himself, especially if the player has good potential. The management must also be wise in seeing the opportunities for players on loan, especially in choosing a club that will provide many playing opportunities.
Yes maybe it is a disadvantage and advantage in itself, but in that choice there is the best choice, so choose the best of all choices. Players will also be happy if they are loaned out to a club that is ready to give them the opportunity to play, because for young players having many minutes to play is certainly a good thing.
If it really gets fatally injured then it will be the biggest loss for a team when lending a player but it all depends on how the player himself plays and where he is loaned because some football clubs sometimes have players who are quite brutal so fights often occur and even injure each other.
If you say a brutal player, in my opinion, Ibrahimovic is one of the players who often injures opposing players.
But for Napoli I am still in awe of those who are able to have good games even though several players are being loaned out to several other clubs.
For next summer, if Napoli can still be like last season, then it is very likely that they will get the title again.