Jose Arnaiz has left Barcelona for Leganes in a €5 million deal, but the Catalan giants have retained a buy-back option for the winger.
Arnaiz joined the Blaugrana from Real Valladolid a year ago, signing with Barcelona B.
The winger struck three goals in the Copa Del Rey last season with Ernesto Valverde's men going on to lift the trophy, thrashing Sevilla in the final.
But the 23-year-old could not force his way into Valverde's plans on a regular basis and he featured just once in La Liga in a five-minute cameo off the bench.
A pelvic injury ended Arnaiz's 2017-18 campaign early, with the winger forced out for the final four months of the season.