He has signed a two-year deal and been loaned out to our sister club, UE Cornella.
Guzman, 28, was available on a free transfer and has been training with Blues since the squad reported back for pre-season.
Guzman has spent most of his career in the third tier of Spanish football, and the past two seasons he was with Catalans UE Olot.
Badalona-born Guzman made 33 appearances for Olot last season, scoring twice, and opted to try out with Blues on the expiry of his contract this summer.
Guzman went with Blues on their pre-season camp to Portugal and appeared in the pre-season friendly against Swindon Town last week.
He can play in various positions across the midfield and also full-back, but as a wideman he serves the team best.
He will now bolster the ranks at UE Cornella, who were knocked out in the Spain's Segunda B promotion Play-Offs last season under the guidance of Xavi Calm, who moved to Blues in July to take up the position of Under-23s Head Coach.