Toon face Wigan Athletic tonight as they slide down the table.
But Jonas told the Sunday Sun: "Now we have young players who recover more quickly and that is going to help us. This is a good opportunity for them, they want to improve.
"I said at the beginning of the season that the young players had to take their opportunities and do well, because in January or next summer there will be new players coming here.
"So they have to do things right, and fight. They have to do their best and work hard for the team and manager, to prove to him that they can play, and help the team."