Bardsley slipped out of the Scotland scene when he fell out of favour at Sunderland under manager Paulo Di Canio. He had defied club orders on drinking when he went to a casino and was photographed lying on the floor surrounded by £50 notes. Having been told he would not play for the club again under Di Canio he appeared to mock their opening day defeat to Fulham on Twitter.
But when Gus Poyet took over as manager he restored Bardsley to the side and he has played regularly at right-back since October. Strachan is satisfied that Bardsley's behaviour under Di Canio will not be an issue for Scotland. The defender has not played for the national side since the 5-1 friendly defeat by USA in May 2012, when Craig Levein was the manager, although he was in Strachan's first squad a year ago.
Bardsley, who was born in Salford but qualifies through his Glaswegian father, could earn a 13th cap in the friendly against Poland in Warsaw on Wednesday, March 5.
Robertson will be called up for the first time after an excellent first season at Tannadice. The 19-year-old has been outstanding at left-back and could add a senior cap to his three appearances at under-21 level.
Fletcher is preparing to play his first match under Strachan. The midfielder's battle with the serious bowel condition ulcerative colitis kept him out of the team at Old Trafford for almost a year and he has not represented his country since a friendly against Luxembourg in November 2012. But the 30-year-old returned for United in December and has played nine times in the past two months, doing more than enough to convince Strachan he is ready to return to the international scene.
Steven Fletcher has not played this month while receiving intensive treatment for an Achilles problem but he is also likely to be included if Sunderland give him the all-clear. The striker is expected to resume full training with Sunderland today, and his club hopes he can feature against Arsenal this weekend or return for the Capital One Cup final against Manchester City on March 2. That is only three days before the Poland friendly but Strachan hopes his main striker will be available.
Fletcher has not started a game since January 22, with the Achilles issue adding to his difficulties in a season in which he has scored only three times in 23 appearances.
The Aberdeen pair, Mark Reynolds and Peter Pawlett, will not be in the squad but both are understood to have impressed Strachan recently and could play their way in for the next friendly, likely to be arranged for the end of May.