Ones to watch: Sime Vrsaljko - Croatia
Age: 26Club: Atletico MadridCaps: 40
Diego Simeone doesn't make it easy for most new signings to break into his Atletico Madrid side, so it speaks volumes of both Sime Vrsaljko's determination and quality that he managed to do exactly that.
A ferociously competitive full-back, Vrsaljko can play on either side of defence and offers equal ability in each half of the field.
Defensively he's strong, resilient and unafraid of making big tackles, while going forward he links sensibly and simply, has good delivery into the area and has the stamina to work up and down the flank all game.
Like many others before him, Vrsaljko had to earn his place in Atletico's side despite being a big-money signing; after showing patience in the early part of the campaign, he established himself as a regular starter and was in the lineup for the Europa League final in May.
First and foremost, Vrsaljko will ensure the back line is secure and take care of his defensive duties.
But in a progressive Croatia side, he will also showcase his ability on the ball, his combination play and willingness to help escape tight situations by playing around the press.
Right-back is the best bet for where he'll feature at the World Cup, though don't rule out a switch across to the left to help out the team at any stage.