José Arnaiz

Barcelona On 25 August 2017, FC Barcelona reached an agreement with Valladolid for the transfer of Arnaiz. He signed a three-year contract with the club three days later, being initially assigned to their B side also in the second division.

Arnaiz made his first-team debut on 24 October 2017, starting the match and scoring the last goal in a 3–0 away win over Real Murcia CF in the round of 32 of the Copa del Rey. The following 3 January, he opened the 1–1 away draw against RC Celta de Vigo also in the national cup; he went on score three times during that competition, only needing as many shots to achieve the feat.

Arnaiz's maiden La Liga appearance took place on 7 January 2018, when he replaced Sergi Roberto late in a 3–0 home victory against Levante UD.

Leganés On 13 August 2018, Arnaiz agreed to a five-year deal with CD Leganés. On 29 January 2020, he was loaned to fellow top-tier side CA Osasuna until June. On 11 July, he scored the winner as the hosts defeated Celta 2–1, and in another win by the same score he added another goal at Barcelona's Camp Nou five days later.

Arnaiz was his team's top scorer in 2022–23, his nine goals helping to a 14th-place finish in division two.

Osasuna On 13 June 2023, as his link to Leganés was due to expire, Arnaiz returned to Osasuna on a two-year contract. He made his debut in European competition on 24 August, as a second-half substitute in the 1–2 home loss against Club Brugge KV in the play-off round of the UEFA Conference League.

Later career In July 2025, the free agent Arnaiz signed a two-year deal with Granada CF.

Career statistics

Honours Barcelona La Liga: 2017–18 Copa del Rey: 2017–18