Rangers interim manager has admitted Danilo and Oscar Cortes have to do more in training to force their way into contention for the starting XI.
Neither forward featured in the starting line-up against Celtic as they were both named on the bench at Ibrox.
Danilo was thrown into the mix in the 93rd minute as he replaced Mohamed Diomande with Cortes an unused sub in the 1-1 draw in the final derby meeting between Celtic and Rangers this season.
Both players have only fairly recently returned from lengthy injury absences with Ferguson cognisant that their efforts in training will likely be in a "totally different training regime", as he branded Ibrox prep on a weekly basis as "really intense".
But, Ferguson - who is in charge until the end of the season, confirmed both players have to do more to force their way into the starting line-up as he hinted they could feature prominently before the end of the season.
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Ferguson said: "They're obviously in the squad. But in terms of picking them, I have a decision - you can only pick 11 players.
"I've watched what happens on the training ground. I see the opposition we've come up against and who'll suit to play against them.
"But everybody's got an opportunity. They just need to work hard to force their way in.
"I think the two of them are good players but they need to do more. They understand that. It's not just a case of you just get in the team for the sake of getting in the team. You need to be in the team on merit.
"I think you ask the two of them, I think they would agree they have to do more. But also you've got to remember they have had long-term injuries. So it has taken a bit of time for them to get up to speed.
"It's probably a totally different training regime than they've had before. Because the training is really intense. But look, that's why you carry a squad. And maybe before the end of the season they may get an opportunity."
