Ki Sung-yueng says he's still not "100%" fit after making his comeback from injury.
The midfielder – who suffered a hamstring injury while away with South Korea for the Asian Cup last month – played 45 minutes of Saturday's friendly against CSKA Moscow, which ended in a 1-1 draw.
Ki is now pushing to be involved in Saturday's home game against Huddersfield Town.
"I don't feel 100% yet, but there's no pain from my hamstring injury," said the 30-year-old, who had been playing week in, week out before ghis Boxing Day departure for the Asian Cup.
"Hopefully, I get better and better and push more in the training. This game, 45 minutes, helped me get more fit."
The CSKA game, played at a chilly Pinatar Arena, came at the end of a five-day training camp in Murcia, Spain.
"It was quite cold, no big difference to Newcastle," said Ki. "At least we got some sun in the training camp. It was a great time, and we can build from here."
The Huddersfield fixture is followed by a February 26 home game against Burnley and a March 2 fixture against West Ham United at the London Stadium.
"I think we have a crucial next three games – it's going to decide our second part of the season," Ki told NUFC TV.
Meanwhile, Sean Longstaff stepped at Newcastle up in the absence of Ki.
The 21-year-old has started the club's last eight league and cup games, and could keep his place against Huddersfield after again impressing in last Monday's 1-1 draw against Wolverhampton Wanderers at Molineux.
Longstaff has been named Match of the day Magazine's young player of the month for January.
"The last month or so has been great for me – I've managed to play some games and played at some top grounds, against some top players," said Longstaff.
"The lads in the changing room have been great – they've helped me loads – and so have the staff. So as much as it's my award, it's a culmination of a lot of people helping me to get to this stage."