Cristiano Ronaldo's injury-time rocket of a free-kick against his former club won the match for the Red Devils, who improved markedly after the break following a dismal opening period.
"It is important in the sense that when we go to Rome I will be able to use all my squad," Ferguson said. "One or two might not travel because there's an important game coming up against Liverpool.
"But we'll still play a team we hope can win the match."
Ferguson was also left to wonder at Ronaldo's winner - barely deserved given United's stuttering display.
"It was a marvellous strike," he said. "He's done it before, he works very hard at that but it was a truly exceptional goal.
"I think that he always wants to do well against his old club because he owes a lot to Sporting Lisbon - they found him as a boy, he respects that and has great admiration for the club."
Ferguson added: "We just marginally won it. We were not a great deal better but increased our game in the second half, more speed and tempo, and managed to just edge it."