Career Mode - Offer the player a loan.
Being able to choose which club you want to loan your player to.
Often, you have some players that are not being used, but you want to take a walk on the team, but you want to choose a club where you will probably be starting, but sometimes you can't play when the teams show where your player doesn't even play on the bench spare.
In real life, you can offer your players to clubs. Why can't you have that option in career mode?