set piece specialist

Does anyone know what a set piece specialist is ?  I have an SPS who has a skill of 20 in set pieces.  Is he better than a non-set piece specialist who has a skill of 60 in set pieces ?

You can check that at: tactics —> player roles :)

Check market price set  SPS îs ok

30 yars players îs 0.50 euros. 20 yars îs 22 euros