ut Scotland boss Craig Levein will not call up any replacement after Naismith was punished for an elbow on Serbia's Srdjan Mijailovic.
A Scottish Football Association statement read: "FIFA have confirmed to the Scottish FA that their disciplinary committee have imposed an immediate two-match suspension on Steven Naismith following an incident that took place during last month's FIFA World Cup Brazil 2014 qualifier against Serbia at Hampden Park."
In-form Celtic winger Kris Commons has been touted for a call-up but Levein will stick with his initial squad for the game against Wales in Cardiff next Friday and Belgium in Brussels four days later.
Levein said: "Obviously this is disappointing news but Steven has been very honest and professional throughout the disciplinary process.
"We named a 25-man squad earlier this week to compensate for any potential suspension, which has now been confirmed, and I am confident we have enough strength in that department to offset the loss of a player who has been in excellent form so far this season."
Television pictures showed Naismith hitting out with his arm while running alongside Mijailovic in the goalless World Cup qualifier at Hampden on September 8.
The incident was not included in the referee or match delegate's report but FIFA later launched an inquiry after being made aware of the off-the-ball incident.
The 26-year-old Everton player could also have missed the away game against Serbia in March if FIFA had imposed the maximum ban.