Radja Nainggolan has been left out of Belgium's 28-man provisional squad for the World Cup, coach Roberto Martinez has confirmed.

Despite being a pivotal figure during the Red Devils' rise to prominence in recent years, the 30-year-old has struggled to fully establish himself under new manager Roberto Martinez.

When the Roma midfielder was left out of the squad to face Gibraltar and Greece at the beginning of the season, Martinez insisted that the decision was a tactical decision, and Nainggolan's chances of  playing for his country in Russia looked intact in November when he was recalled for friendlies against Mexico and Japan. He was also included in the squad to play Saudi Arabia in March.

However, on Monday Martinez confirmed that Nainggolan will be missing out despite playing a key role in the Giallorossi's run to the Champions League semi-finals. "First and foremost, we all know Radja is a top player, there is no question about that," the coach told a news conference. "It is a tactical reason. In the last two years, the team has worked in an offensive way, in a very specific manner. NAINGGOLAN REFUTES 'STUPID' CLAIMS "In the case of Radja, we all know he has a very important role at club level and I don't think we can give him that in the national team. "I travelled to see him yesterday in Rome and we had a very good conversation. The decision is not an easy one, I understand how popular the player is, but we have to create the team to try to become a winning team. "It is purely a tactical decision." Martinez has named a 28-man provisional squad for the tournament, meaning there are places for the likes of Christian Benteke and Nacer Chadli, despite disappointing campaigns in the Premier League for Crystal Palace and West Brom respectively.

  Michy Batshuayi is also included, despite suffering a season-ending ankle injury while in action for Borussia Dortmund in April. Belgium head into the tournament as one of the favourites given the strength in depth which Martinez is able to call upon. Thibaut Courtois is likely to start in goal ahead of Simon Mignolet while the likes of Toby Alderweireld, Vincent Kompany, Jan Vertonghen and Thomas Vermaelen battling for places in defence. Mousa Dembele, Kevin De Bruyne and Marouane Fellaini are in contention for midfield places while Romelu Lukaku is likely to lead the line, supported by Eden Hazard and Yannick Carrasco. The full squad: Goalkeepers: Koen Casteels (Wolfsburg), Thibaut Courtois (Chelsea), Simon Mignolet (Liverpool), Matz Sels (Newcastle); Defenders:  Toby Alderweireld (Tottenham), Dedryck Boyata (Celtic), Laurent Ciman (Los Angeles FC), Christian Kabasele (Watford), Vincent Kompany (Manchester City), Jordan Lukaku (Lazio), Thomas Meunier (Paris Saint-Germain), Thomas Vermaelen (Barcelona), Jan Vertonghen (Tottenham); Midfielders: Nacer Chadli (West Brom), Kevin De Bruyne (Manchester City), Mousa Dembele (Tottenham), Leander Dendoncker (Anderlecht), Marouane Fellaini (Manchester United), Youri Tielemans (Monaco), Axel Witsel (Tianjin Quanjian); Forwards: Michy Batshuayi (Chelsea), Christian Benteke (Crystal Palace), Yannick Carrasco (Dalian Yifang), Eden Hazard (Chelsea), Thorgan Hazard (Borussia Monchengladbach), Adnan Januzaj (Real Sociedad), Romelu Lukaku (Manchester United), Dries Mertens (Napoli).