DATE OF BIRTH*15 May 1993
BIRTHPLACEOlomouc, Czech Republic
Born in Olomouc, Czech Republic on 15 May 1993, Tomas joined Chelsea full-time in January 2011 having signed a pre-contract agreement with the club the previous summer.
He spent the first half of the season at his former club, Sigma Olomouc, but trained with Chelsea in midwinter prior to making his debut in the reserves, followed by the youth team in February, going on to make 10 reserve team appearances as we tied up the national league title.
A right-sided centre-half who can play right-back, he made his first-team debut for Sigma Olomouc in 2009/10 and is very athletic and quick and good at one-on-one defending. He is also comfortable on the ball.
In August 2011, he signed on loan with Vitesse Arnhem and, after quickly establishing himself in the side, went on to make 37 appearances and score one goal as the Dutch team finished seventh in the league.
He spent the 2012/13 season at the same club, having in July 2012 signed a contract extension with Chelsea committing him to the club until the summer of 2017.
Kalas netted his first goal of the season in Vitesse's 3-0 win at FC Groningen and enjoyed another impressive campaign.
In February 2013 he won his nation's award for the best young player of the year, sharing a stage with Petr Cech who was collecting the Czech Footballer of the Year honour.
Kalas returned to Chelsea for the 2013/14 season with Jose Mourinho making him part of the first team squad, although a small leg fracture kept the young player out in the early weeks. He made his debut for the club in the 2-0 Capital One Cup victory at Arsenal, appearing as a last-minute substitute.
He made his Chelsea debut as a late substitute in a 2-0 Capital One Cup win over Arsenal at the Emirates.
He then made his European bow for the club, again as a late sub, in our 2-0 Round of 16 second-leg win over Galatasaray at Stamford Bridge.
The young defender was handed his first start for the club in our 2-0 win at Liverpool in April 2014, playing alongside Branislav Ivanovic and impressing with a mature display against previously freescoring opposition.
On the final day of the season he made his second start in our 2-1 win at Cardiff City.
In June 2014 it was announced Kalas would be moving on loan to FC Cologne in the Bundesliga. On 9 January he switched to Middlesbrough in the Championship for further loan experience. There he made 17 appearances in a positive spell as Boro challenged at the top, although loan regulations meant he had to return to Chelsea before the Teesiders participation in the play-offs.
However he returned to Middlesbrough for another season-long loan in 2015/16. He made a major contribution to the Teeside team's promotion back to the Premier League, playing 26 league matches and 30 all competitions.
Kalas moved to Fulham on loan for the 2016/17 season, brought to Craven Cottage by former Chelsea midfielder Slavisa Jokanovic.
The defender played regularly and performed consistently well, scoring his first goal for the club in a 5-0 win over Huddersfield. He made 40 appearances in 2016/17 and helped Fulham reach the promotion play-offs where they were beaten by Reading.
Kalas's impressive form at club level also earned him further international recognition for the senior Czech Republic side and he was part of the squad which travelled to China and Singapore for our summer tour in 2017. Kalas came on as a second-half substitute in our opening game against Arsenal.
He then signed a new four-year deal at Chelsea before returning to Fulham on loan for the 2017/18 campaign, when he helped the Cottagers get promoted back to the Premier League. He made 33 league appearances, 29 from the start, and was brought on in the play-off final with Fulham down to 10 men and a crucial defensive job required to see out the 1-0 win.
In August 2018, he returned on loan to the Championship, this time with Bristol City.
Having played for Czech Republic Under-17s, Under-18s, Under-19s and Under-21s, he made his full international debut in November 2012, coming on as a sub in a friendly win over neighbours Slovakia.
He was named in the Czech squad for the 2015 European Under-21 Championships when they were host nation and having missed the opening match due to suspension, played the next two as they were eliminated at the group stage.
He earned another full international cap when he came on during a Euro 2016 qualifer win away to the Netherlands in October 2015. In 2016/17, during his loan at Fulham when he was a regular for the Championship side, he was a regular in the Czech squad and earned further caps, including a start against Begium in June 2017.