Scotland forward Steven Naismith believes nobody in the squad can say they are certain to face Slovenia on Sunday. And the Norwich player sees Wednesday's friendly against Canada as an important opportunity for all players to stake their claim. Scotland face a crunch encounter at Hampden at the weekend following successive 3-0 defeats against Slovakia and England in their World Cup qualifying group. Manager Gordon Strachan made eight changes for the Wembley game and Naismith feels competition for places has never been stronger. And, with four uncapped players in the squad - Leeds defender Liam Cooper, Bournemouth winger Ryan Fraser, Fulham midfielder Tom Cairney and Celtic's Stuart Armstrong - the Easter Road encounter could help shape Strachan's team selection for the competitive clash. Naismith told the Official Scotland Podcast: "The new guys in the squad, if they play, they will see it as an opportunity to say 'I'm here to stay'. "Guys like myself who have not played many games recently for the national team, I've got to make sure the manager sees that I'm still worthy of being in the squad. " It goes back to competition for places, if you're not performing you are not going to be in this squad eventually. "That's what it is for players who have just come in and have maybe not had much game time for the manager recently. "And, again, for the players that have been playing, it's for them to say 'I should be in the team for Sunday'."Obviously some of the results in the campaign haven't been what we wanted so I don't think anybody is sitting here saying 'I am playing on Sunday, I know I'm in the team because I have been good enough'."