Tottenham ace Dier, who can operate as a defender or as a midfielder, featured for England in their final group game against Belgium at the World Cup on Thursday.
The 24-year-old started the match and played for the entire 90 minutes, as the Three Lions lost 1-0.
Former Arsenal and England international star Merson has stated that he was disappointed with the performance of Dier, who earns £70,000 per week as salary, according to The Daily Star.
Merson wrote in The Daily Star: “I was really disappointed with Eric Dier. I thought he was far too casual, gave the ball away cheaply and was trying to play 40-yard passes when he should have kept it simple.
“I pushed for him to start because I thought we’d need him later in the tournament next to Jordan Henderson to give us more protection. But he really didn’t do himself any favours and Gareth might think twice now.”
Place in doubt
Prior to the match against Belgium, Dier has come on as a substitute in the third minute of injury time against Tunisia and did not play at all against Panama.
It is hard to see England manager Gareth Southgate include the former Sporting Lisbon star in the starting lineup against Colombia in the last-16 tie next week.