Liam Bridcutt, the Brighton and Hove Albion midfielder, George Boyd, the Peterborough winger on loan at Hull City, and Dundee United's Gary Mackay-Steven are the three new faces in the 28-man group, while there were also recalls for Danny Fox of Southampton and West Bromwich Albion's Graham Dorrans. Injury rules out Scott Brown, while Phil Bardsley, Lee Wallace, Matt Phillips and Jamie Mackie also all drop out from last month's friendly match with Estonia.
There was also no place for Leigh Griffiths, the joint top goalscorer in the Clydesdale Bank Premier League this season with 19 goals, although Strachan admitted the on-loan Hibernian striker had come very close to being included.
"It's all about form," said Strachan. "If they weren't playing well they wouldn't come into our thoughts or into the process of deciding what the squad is.
"Some players, at different times in the season, are feeling better than others. You have to pick players who, when they go on the pitch, are feeling good about themselves.
"That's one of the reasons why the squad has been picked this way. I spoke to three players yesterday [who have been left out] and they were good about it. It's very hard to tell somebody they are not included in a squad, but they understood it."
Strachan admitted Griffiths had been unlucky to not make the cut. "Leigh was very close to making the squad and can count himself as very unfortunate," he added.
"We did have a lot of conversations about him on Monday and Tuesday – Stuart [McCall, Scotland coach], myself and Mark [McGhee, his assistant manager]. He's unlucky that we have people who are on form like [Steven] Fletcher and [Jordan] Rhodes who are always going to score goals, plus [Shaun] Maloney can play up there as well.
"Leigh was very, very close that's for sure. The decision came down to this morning on that one."