But the defender's set to start for the Republic of Ireland in their two-legged World Cup play-off against Denmark.
Clark has spoken about Rafa Benitez's decision to drop him last month on his return from international duty.
Meanwhile, Benitez has a message for his players in the wake of Saturday's 1-0 defeat to Bournemouth, which was watched by a delegation of coaches from his native Madrid.
Here's your daily briefing:
Clark hasn't started a Premier League game in more than a month.
Fit-again Florian Lejeune was recalled to Benitez's team at the expense of Clark after last month's home game against Liverpool.
However, Clark came off the bench against Bournemouth on Saturday after captain Jamaal Lascelles was forced off with an ankle problem.
While frustrated, Clark says he accepts the decision of Benitez.
“I felt I was playing well myself, but there was a league game (against Southampton) a couple of days (after Ireland’s win over Wales), and that was the decision the manager made,” Clark told the Irish Examiner.
“Every player wants to play, and I was coming off the back of two good results, but it’s the manager’s decision.
“He’s experienced enough – his CV and his record shows that. If he says that, I’m happy to go with it. Obviously, it’s frustrating sitting on the bench, but I’ll keep working hard.”
Benitez bemoaned the "mistakes" his team made against Bournemouth, who scored an injury-time winner.
And United's manager wants his players to learn from their errors – and quickly.
“We have to learn quickly what it means in the Premier League and what it means to make mistakes,” said Benitez. “It’s not like in the Championship when you make mistakes and you can win. If you make a mistake, you pay for that."
Why are we waiting? Is no news, good news?
Several potential buyers remain in talks with Newcastle, which was put up for sale by owner Mike Ashley last month.
But time is running out for a takeover to be completed ahead of the January transfer window, when Benitez hopes to strengthen his squad.
Newcastle need to win at Boundary Park tonight to progress to the knockout stages of the Checkatrade Trophy.
Peter Beardsley’s Under-23s take on Oldham Athletic (7.30pm kick-off) in their final Group D game.
The club is third in the four-team group after a win and a draw. Oldham are in second place and just need a draw to progress at the expense of United.
Fit-again midfielder Dan Ward said: “It’d give everyone a massive lift. It’d be great to go there and get the win, and that’s what we need to do to qualify. It’d be fantastic for everyone.”
Newcastle fans will be hosed in the Chaddy End, and admission will be £10 for adults, £5 for concessions and £1 for under-16s.
The club today revealed it had formed an official Newcastle United Former Players Association.
United managing director Lee Charnley said: “The Former Players Association is a fitting legacy for the club's 125th Anniversary year.
"It will recognise and support every player that has contributed to the history of Newcastle United.
"We are committed to ensuring its success and, through our Foundation, to providing the resources it will need to grow and develop long into the future.”
The association will be formally launched tonight at the Newcastle United Foundation’s 125 Years United Dinner.
Benitez welcomed some special guests to St James's Park at the weekend.
Writing on his website, Benitez said: "This weekend, we had the privilege enjoying a visit from the representatives of the Madrid Coach Committee, an association belonging to the Madrid Football Federation.
"We had the chance to share experiences, points of view and knowledge with the ten representatives who visited our stadium, before the Bournemouth clash on Saturday and in our sports facilities in Benton, showing them the Newcastle United Academy.
"For me, as always, this was a rewarding experience and I think it was the same for my work team.
"We'd like to express our gratitude to the Madrid Football Federation and to the Madrid Coach Committee for this pleasant visit."