For many, the former Newcastle United left-back has been the signing of the season.
Carragher told LFC TV: "He's settled in really well, you can see that in his performances. He mixes in well with the lads, has a laugh and a joke.
"I'm very surprised he hasn't had a Spain call-up. It makes you realise how strong Spain must be, because I can't think of a left-back who's performed better than him at this stage of the season.
"You wonder what they've got at left-back, but if he keeps performing the way he is he's got a chance of getting in for the Euros in the summer.
"Spain are a great team but their weak position is left-back. That is a position that's up for grabs, so with the way he's playing for a top club, he deserves a chance."