Marcos Alonso Mendoza (born 28 December 1990) is a Spanish professional footballer who plays as a left-back, left wing-back or centre-back for La Liga club Barcelona and the Spain national team.
Alonso started his career with professional career Real Madrid but went on to make his name with Bolton Wanderers in England and later with Fiorentina in Italy. His success at the latter club led Chelsea to sign him for an estimated £24 million in 2016, going on to win multiple honours with the club including a Premier League and UEFA Champions League title.
Alonso made his full debut for Spain in March 2018.
Club career
AD Unión Adarve
Before signing for Real Madrid, a young Alonso started his career at AD Unión Adarve.
Real Madrid
At some point, Alonso joined Real Madrid's youth academy, going on to represent every youth side in the following years. In 2008, he reached Real Madrid Castilla which competed in Segunda División B, and first appeared for the reserve team on 22 February 2008, playing the entire match in a 1–0 home loss against AD Alcorcón.
On 11 December 2009, Alonso was first summoned by the main squad – coached by Manuel Pellegrini – for a La Liga match at Valencia CF. Eventually, he did not make the final list of 18, and his debut arrived on 4 April of the following year as he came on as a substitute for Gonzalo Higuaín in the 90th minute of a 2–0 win away to Racing de Santander.
Bolton Wanderers
Alonso joined Bolton Wanderers of the Premier League for an undisclosed fee, on 27 July 2010. He made his competitive debut for the club in a League Cup 1–0 away win against Southampton on 24 August; his first league appearance arrived on 1 January 2011, starting for suspended Paul Robinson in a 2–1 away loss to Liverpool at Anfield.
Alonso scored his first goal for Bolton on 31 March 2012, netting the second in an eventual 3–2 success away to Wolverhampton Wanderers. At the end of the 2012–13 season, he was voted The Bolton News player of the year, winning 37% of the vote: Marc Iles wrote, "...this has been a break-out season for the former Real Madrid starlet. Alonso has grown in stature and become a consistent performer at full-back – chipping in with some important goals too."
Fiorentina
In May 2013, Alonso signed for Italian side ACF Fiorentina on a three-year deal, despite being offered a new contract by Bolton manager Dougie Freedman. As he was under the age of 23 when leaving, Fiorentina were forced to pay Bolton £400,000 compensation.
On 30 December, after the player had made nine official appearances, Sunderland boss Gus Poyet announced that he would join on 1 January 2014, on loan until the end of the campaign.
Alonso played his first match with Sunderland on 7 January 2014, featuring the full 90 minutes in a 2–1 home win over Manchester United for the League Cup semi-final first leg and being given the man of the match award by Sky Sports. He played in the final of the competition on 2 March, not being able to prevent a 3–1 loss against Manchester City; he contributed with 20 appearances all competitions comprised, helping his team retain their top flight status.
Upon his return from loan, Alonso became a regular, amassing over 70 appearances in his final two seasons in purple. On 19 March 2015 he scored his first goal for the Viola, in a 3–0 win away to fellow Italians A.S. Roma for the round of 16 of the UEFA Europa League.
Chelsea
On 30 August 2016, after 85 appearances and five goals overall with Fiorentina, Alonso completed his move back to England after signing a five-year contract with Chelsea worth around £24 million. He made his debut on 20 September, playing the full 120 minutes in a 4–2 win away to Leicester City for the EFL Cup, and four days later he first appeared in the league in a 3–0 away defeat to Arsenal, coming off the bench for Cesc Fàbregas in the 55th minute.
Alonso scored his first goal for the club on 5 November 2016, in a 5–0 victory over Everton at Stamford Bridge. He added two more at the King Power Stadium, in a 3–0 win against Leicester on 14 January 2017.
In April 2018, Alonso came under extensive criticism for seemingly purposely digging the studs of his boots into Shane Long's leg during a tackle in a league game against Southampton. He was not reprimanded in any way by referee Mike Dean – who came under similar criticism – but was later charged with violent conduct by The Football Association, and later issued a three-match ban.
Alonso opened his goal account of the 2018–19 season on 18 August 2018, scoring the 3–2 winner in the 81st minute of the home fixture against Arsenal.