Middlesbrough are set to sign Chelsea defender Tomas Kalas on a permanent deal, according to reports from The Sun.

Kalas spent the last 16 months on loan at Middlesbrough and played a key role in helping the Teesside outfit claim promotion to the Premier League this season.

Now according to reports, it has been claimed that Boroh are set to sign the 23-year-old on a permanent deal this summer.

Czech Republic international Kalas, who joined Chelsea from Sigma Olomouc in 2010, made 26 Championship appearances for Boro this term.

Kalas had previously expressed his desire to stay put at the Riverside Stadium by telling the Evening Gazette: "I don't know how many games I've played since I came - probably around 40, which is not bad in one and a half years.

"That's why I came here, to play games and hopefully I'll keep playing next season - maybe here. If I could get the deal [to move to Boro permanently], I would really think about it. Yes, why not?"