Jordan Robinson is the latest to be sidelined after suffering a hamstring strain early in the midweek 4-0 defeat to Curzon Ashton, a result which effectively secured promotion for the visitors.
The Ashton-under-Lyme club are nine points in front of Warrington Town with a game in hand, having created a 12-point lead over third-placed Quakers on Wednesday, when the majority of the 1,429 crowd departed disappointed.
It was the club's second highest gate this season, though some left after Curzon stormed into a 3-0 lead early in the second half, before adding the fourth in the final minute.
Gray remains positive, saying: "I can't see Curzon not winning the league now, but you've got to look where this club started 18 months ago."
Gray, who takes his team to Prescot Cables in Merseyside today, added: "We've come a long way in that time. We had no players, but we've come an awful long way in a short space of time and now we're third off top in the league above.
"Now the job is to go and win the play-offs. There's no point talking about what happened on Wednesday, we've got to forget about it. Now it's about what we do going forward.
"There's nobody at the club more positive than me and I've got one objective in mind and that's to win the play-offs.
"You want the pressure, you want to be challenged and you've got to be able to handle it.
"We've had a fantastic journey until now and we're still on that road. We've got ten remaining games, hopefully, and now we've got to get players fit for the most important stage of the season."
Robinson will be missing today, while Chris Hunter (ankle) and Leon Scott (hamstring) have both been injured of late. Stephen Harrison, Gray says, was unavailable in midweek due to work commitments.
The manager added: "Jordan's got a slight hamstring problem so will be missing for a week or maybe more, so we've got to be careful with what we've got.
"We're looking to bring in more players because we've got to strengthen the squad.
"We've had a good run of form. We'd won 14 out of 16 games, we must be the most in-form team in the league. Form hasn't been an issue, we've won more than we've lost, but we need players back from injury.
"We've got to start again and put an arm around the players to pick them up. That's our job as coaches. We need to regroup straightaway."
Gray remained phlegmatic in the wake of Wednesday's defeat, the heaviest of his managerial career.
It was Quakers' worst since losing 5-0 at Lincoln City in April 2012.
Although pointing out that the wind dropped after Darlington kicked into it in the first half, he did not use the conditions as an excuse.
He said: "We were glad to be only 1-0 down at half-time. It was so important not to concede a second goal before half-time to try and stay in the game.
"We knew the conditions would go against Curzon in the second half. Having said that, the wind did drop.
"But you have those nights sometimes - the wind drops and we made mistakes. It was a bad night at the club, but you've got to stay positive otherwise what's the point of being in this business?"
In contrast to Curzon, who have now not conceded a goal in six matches, 18th-placed Prescot have kept one clean sheet in nine fixtures and have won one game in that time.
The Merseyside team drew 2-2 with Quakers in October, when Darlington conceded twice at home for the first time this season.
They have now conceded 32 goals in 34 games, the second best record in the division after Curzon, who have strung together six successive clean sheets.
Gray added: "We've got to be positive and we've got to get back to keeping clean sheets. That's what Curzon are about. They've won numerous games 1-0.
"They've had a lot of clean sheets and we have been like that until last Saturday, so we've got to get back to being hard to play against. We'll do that, we'll get back to the training ground."