Wilshere was left out of the England squad by manager Gareth Southgate for their friendlies with Germany and Brazil, despite a number of players dropping out through injury.
The Arsenal midfielder has been a regular in the team for Europa League and Carabao Cup fixtures but has made just two appearances in the Premier League.
Southgate said his decision to omit Wilshere was because he didn’t think the 25-year-old was being used in his best position.
And Merson believes Wilshere must consider leaving Arsenal in January to push for a place in England’s squad for the World Cup next summer.
“I don’t think Jack is a ten,” Merson told Sky Sports News.
“I think he is a deeper player, but he is not playing deeper. You’d have to ask Arsene [Wenger] why that was.
“He [Southgate] has called up Jack Cork, who I like and think is a good player, but Jack Wilshere has got to move.
“It is alright Arsene Wenger saying a fit Jack Wilshere gets in the England team, but you have to play for Arsenal. But at the same time, [Jesse] Lingard has started less games than Wilshere.
“The way he plays, I think going abroad probably suits him and his game, otherwise he is going to go to a relegation-battling team, and that is not his game.
“He needs to get on the ball and play football and be in a team that really are going to have a lot more of the ball than not. So probably abroad to an AC Milan or somewhere like that.”