Casto as a Betis player in 2011
|Full name||Casto Espinosa Barriga|
|Date of birth||18 June 1982|
|Place of birth||Pueblonuevo del Guadiana, Spain|
|Height||1.81 m (5 ft 11 in)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 21 May 2017.
Born in Pueblonuevo del Guadiana, Badajoz, Extremadura, Casto spent four years at local Mérida UD all levels comprised, making seven league appearances for the seniors in Segunda División B. In 2003, he moved to CD Logroñés where he played one season before joining Albacete Balompié in Segunda División, appearing once for the first team during 2005–06.
Real Betis purchased Casto in the 2006 summer, where he initially began as third-choice behind Pedro Contreras and Toni Doblas. With the arrival of Portuguese international Ricardo in the following campaign, it seemed as though he would be provided with little opportunity to shine, even with Contreras' departure. However, after a serious injury to Doblas, he was called up from the reserves; after Ricardo also went down with a minor ailment, he made his debut in La Liga on 16 December 2007, against UD Almería in a 3–1 home win.
In March/April 2008 Casto, who eventually overtook Ricardo as first-choice after the latter's recovery, featured in Betis' first three back-to-back victories in over two years, with wins over CA Osasuna, FC Barcelona and Real Zaragoza. In his first five games Betis won four, with the player keeping clean sheets in three.
As coach Francisco Chaparro stayed on the bench for 2008–09, Casto won the battle for first-choice over Ricardo, being the side's undisputed starter during the early stages, a situation which would revert midway through the season. He was mainly used as a starter after Ricardo's departure to Leicester City, only being overtaken by Adrián in 2012–13.
- "Real Betis 3–1 Almeria". ESPN Soccernet. 16 December 2007.
- "Valladolid 0–0 Real Betis". ESPN Soccernet. 23 December 2007.
- "Osasuna 0–1 Real Betis". ESPN Soccernet. 23 March 2008.
- "Real Zaragoza 0–3 Real Betis". ESPN Soccernet. 6 April 2008.
- "Ricardo vuelve a ser el portero titular del Betis" [Ricardo is Betis' starting goalkeeper again]. Diario AS (in Spanish). 9 January 2009. Retrieved 20 March 2017.
- "Casto se despide del Betis bajo los palos" [Casto bids Betis farewell behind the sticks] (in Spanish). El Desmarque. 30 May 2013. Retrieved 1 July 2015.
- "El Murcia ficha a Casto e Iván Moreno y renueva a Dos Santos" [Murcia signs Casto and Iván Moreno and renews Dos Santos]. Marca (in Spanish). 24 July 2013. Retrieved 1 July 2015.
- "Casto, nuevo portero de la UD Las Palmas" [Casto, new goalkeeper of UD Las Palmas] (in Spanish). UD Las Palmas. 28 August 2014. Archived from the original on 21 June 2015. Retrieved 1 July 2015.
- "Casto, un portero con experiencia, se convierte en el cuarto fichaje del Almería" [Casto, an experienced goalkeeper, becomes the fourth signing of Almería] (in Spanish). UD Almería. 2 July 2015. Archived from the original on 2 July 2015. Retrieved 2 July 2015.