"At this moment in time both Mark and Dwayne won't be on the plane. But their task now is to try and stay positive, to remain focused and stay fit as I'm sure they were both just outside that squad," said Jones.
"And as such they've got to be the first people on the plane if there is an injury."
With a month of the season still left to play before the Lions leave for South Africa, followed by a grueling fixture list in arguably the world's most-physical rugby nation, Jones would not be surprised to see Cueto or Peel called up to the squad at some stage over the next 10-and-a-half weeks.
"The key thing for those two now is to keep believing and to ensure that if anything does happen over the next few weeks, then they are ready to step in straight away.
"I can guarantee that over the next few weeks at least three or four of those players picked will get injured and won't make the trip. And I can also guarantee that once they are out there, at least another four or five will have to come home.
"They are taking a small squad out to South Africa so there will be a harder edge in training and they will have injuries. That's not to rain on those guys' parade - it's just the nature of top-class rugby."
Cueto has first-hand experience of the type of situation Jones has described having won a late Lions call up prior to departure for New Zealand four years ago.
In 2005, Cueto failed to win a place in Sir Clive Woodward's original touring party but he eventually boarded the plane after injury ruled out England colleague Iain Balshaw.
Cueto went on to win a Lions Test cap in the third international against the All Blacks, while Peel, who moved to Edgeley Park from the Scarlets last summer, featured in all three Tests in New Zealand.
Jones believes both Cueto and Peel were extremely unlucky to miss out this time but that both players must react positively for their own sakes and for the sake of their club.
"I don't know whether Mark has missed out to Ugo Monye or Leigh Halfpenny, but I'm just hoping that he responds well," he added.
"He's been playing really well and has been in great form both for us and England. I just hope he can take this on the chin and doesn't let it affect his performance at the weekend.
"He's a strong man and knowing Mark he'll want to go out for us against Northampton on Saturday and show Ian McGeechan that he's made a wrong decision.
"It's exactly the same with Dwayne. I'm again very, very surprised he's not there.
"Dwayne's had a lot of bad luck with injuries this season but no-one else has jumped out of the page to really make their mark as a Lions scrum-half.
"I'm very disappointed that both Mark and Dwayne aren't in the squad. In fact I was quite down coming out of the TV room after hearing the news.
"I felt sure that if both of them had made the trip then they would have gone on and made the Test side."