Spanish news agency EFE reported on Wednesday evening that the players of second division team Alaves were robbed earlier in the evening whilst out on the training field, dpa reported.
An individual, who has still not been identified, allegedly entered the team's dressing-room and helped himself to mobile telephones, cash, credit cards and jewellery.
The suspect was spotted by one of the club's physio's and escaped in a car, only to be arrested later by the police. However, none of the stolen objects have so far been recovered.
The incident took place at Alaves' training ground in Ibaia, on the outskirts of the Basque regional capital Vitoria.
Alaves - who surprisingly reached the UEFA Cup final in 2001 - are third from bottom in the second division and in the midst of a grim relegation struggle.