Grounds signs new Middlesbrough deal
Grounds was nearly released by Boro over the summer but has this season stepped into the first team and subsequently handed a two-year deal.
"We're very pleased with his progress this season," Gareth Southgate told the club's official website.
"We didn't expect him to progress this quickly but he got into the first team and did very well, showing he has the right character and mentality to cope with the big occasion.
"He's still very young and has a lot to learn, but his progress has been good enough to earn another deal."