"Every coach is praying that their players come back fit [from international duty]," said Ferguson.
"I have to make sure I have some freshness in the team because we also have Chelsea on [Tuesday].
"It is a big ask for our squad and something we need to concentrate on because I need to make sure I pick the right teams."
The resumption of the league programme sees City, Chelsea, Tottenham Hotspur, Arsenal and Everton resume their five-way battle for the three Champions League places below United. Chelsea, four points off City in third place, visit Southampton tomorrow, while fourth-place Spurs are at Swansea City and fifth-place Arsenal host second-bottom Reading.
Everton, two points behind Arsenal in sixth, tackle Stoke City.
Spurs' momentum has begun to ebb in recent weeks, following consecutive defeats by Liverpool and Fulham, and Arsenal are now only four points behind their local rivals with a game in hand. Arsene Wenger's men, however, will once again be without Jack Wilshere, who has an ankle injury, while the injury-prone Abou Diaby has been ruled out for up to nine months with knee ligament damage.
Arsenal are also likely to encounter a Reading side invigorated by the mid-week appointment of manager Nigel Adkins, who has eight games to bridge the seven-point gap that currently separates the club from safety.
Third-bottom Wigan Athletic preserved the three-point gap that separates them from the teams above the drop zone with a last-gasp 2-1 win at home to Newcastle last time out.
Roberto Martinez's side, who also have a game in hand, host Norwich City tomorrow and victory will lift them out of the relegation zone at the expense of Aston Villa, who do not welcome Liverpool to Villa Park until Monday.AAP