Newcastle face Leicester at St. James' Park on Saturday afternoon.
The 24-year-old has missed the Toon's last four Premier League outings after suffering a foot injury during the 1-0 loss to Bournemouth, where he was forced off the field of play in the 55th minute.
Since dropping out of the side, Newcastle have earned just one point from a possible 12 after suffering losses to Manchester United, Watford and Chelsea, picking up a solitary point thanks to a two-goal comeback away at West Brom.
Newcastle are desperately missing the defensive leadership of their captain, and Lascelles remained coy when talking about his availability to face 2015-16 Premier League champions Leicester on the weekend.
"I trained for the first time today, " Lascelles said, on Tuesday evening. "It gave me a good indication of my fitness and how my foot is holding up. I'll be training again tomorrow and probably get a bit more intense. I'll see how I get on.
"I've said it before, it's hard to watch. The team is not doing great and watching I feel a bit responsible. I'm going to try everything to get back playing as soon as possible - fingers crossed it can be Saturday."
Newcastle will be up against an in-form Leicester side that has seen new manager Claude Puel lose just once in his six games in charge to Manchester City, picking up wins against Everton, Tottenham and Burnley.
However, three points could see the Magpies shoot straight back up the league from 15th place, and they will stand more chance of doing that if former Nottingham Forest ace Lascelles can declare himself fit in time.