Fletcher has not featured since damaging his ankle ligaments on Scotland duty in March and Sessegnon was sent off in the 6-1 defeat by Aston Villa on Monday - a three-match ban ended his campaign.
That leaves Sunderland going into the final three games with a squad that has only scored 21 goals all season, but Di Canio insists he has enough strike power as he prepares his squad for a home clash with Stoke, where three points would go a long way to securing their Premier League future.
"I don't talk about Stephane because he is out, I will focus my attention on my [remaining] players," Di Canio said.
"We have enough quality to score goals to win games, especially because we play at home, which is really important.
"It means 39,000, 40,000 people are pushing for the players, which gives them extra adrenaline and motivation to give their best.
"We have quality. Danny Graham hasn't scored yet, but now I am sure the time has come when he will score because in the next few games, he will be crucial.
"We have Adam Johnson who is capable of scoring. We have different ways to damage the opponent, so I am not worried, to be honest.
"I am not the kind of manager who cries - obviously I would like to have all my players available and many options. But it's not possible and we are going to find a way to damage the opponent.
"I won't tell you now if we are going to change formation, if we change the system, but we are going to put on the field the best team we can to win the game and get three points."
Sunderland will start the weekend five points clear of the relegation zone despite the drubbing at Villa Park, but know their situation could have worsened by the time they kick off against the Potters at the Stadium of Light.
It will be their second successive Monday night fixture, but Di Canio believes that can only be an advantage at this stage of the season.
He said: "It's an advantage, not a disadvantage, because if we are talking about what is going on on Saturday, if Wigan win, if Villa win, if Newcastle win, we have to win anyway; if they lose, we have to win anyway.
"Just because we fell in a trap the week before, I don't think we are so stupid.
"Whatever happens to the others, we are not going to underestimate this game because this slap was too much.
"Now we have a big, big scar showing on our body which reminds us if we play like that, we can have another one.
"We are not masochistic people, so I am sure we are going to perform properly.
"It doesn't mean that we are going to win 3-0, it means we are going to perform in terms of commitment, desire, concentration, dedication like we did against Everton and Newcastle. That's for sure."