Former Scotland and Rangers striker Billy Dodds has labelled Gordon Strachan's lack of faith in Leigh Griffiths as a costly mistake.
The Celtic striker made a big impact in the second half of the World Cup qualifiers, but it was not enough to help Scotland reach the play-offs.
He said: "If Leigh Griffiths had started the campaign we probably would have qualified. There were things not right at the start of the campaign, and that's what cost us."
Griffiths missed the first three games of the qualifiers, of which Scotland won only one.
The Celtic forward has been in terrific form over the past three seasons and hit an impressive brace against England at Hampden Park back in June.
Scotland have not qualified for a major tournament since France '98 and failure to beat Slovenia in their final group game proved costly.
Strachan's side finished third in the group, behind Slovakia on goal difference, eight points back from group winners England.