Team Player, called Counter Mastery before being unlocked, is a passive ability only available to Ruby Rose in RWBY: Grimm Eclipse. It must be unlocked by successfully performing 300 counters as Ruby. This ability increases the chance to trigger a Team Attack when you counter an enemy as Ruby. It costs 1 point to use.
Early Access Edit
Team Player replaced Armor Piercing Rounds, called Sniper before being unlocked, was a passive ability only available to Ruby Rose in RWBY: Grimm Eclipse during Early Access. It needed to be unlocked by leveling Ruby to level 10 at least once. This ability changed Ruby's bullets into Armor Piercing Rounds, enabling them to damage tougher enemies.