The Blues centre-half is stuck in the club's loan system but will make his first move to La Liga
US men's national team defender Matt Miazga has completed a season-long loan deal from Chelsea to Alaves until June 2022.
The Liga club will also have an option to buy the 26-year-old, who embarks on his fifth loan in his fifth different country.
It comes with Miazga having made just two appearances for the Blues since his £3.5 million ($5 million) transfer from New York Red Bulls in 2016.