Image: Erik Pieters was left out of the Stoke squad for the match with Everton after breaking a club curfew

Stoke defender Erik Pieters was dropped from the matchday squad to face Everton on Saturday after breaking a club curfew, Sky Sports News understands.

Manager Paul Lambert had planned to start Pieters in the game at the bet365 Stadium, but opted for Kostas Stafylidis after learning that Pieters had been at nightclub with his wife on Friday evening.

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There is no suggestion Pieters was drinking alcohol, but Lambert was determined to stick by his squad-whole rule that no player can attend a social event where alcohol is served within a 48-hour period leading up to a game.

Stoke were defeated 2-1 by Everton with Cenk Tosun scoring either side of an Eric Maxim Choupo-Moting strike.

Highlights: Stoke 1-2 Everton

The Potters sit in 19th on 27 points, three adrift of West Ham in 17th with seven matches remaining.

They are without a win in the Premier League since January 20 and face Arsenal at the Emirates Stadium in their next fixture on April 1, live on Sky Sports Premier League HD.