As good as Longstaff is, and as tempting as it may be for Steve Bruce to go like for like by recalling Isaac Hayden after suspension at West Ham on Saturday, the United manager has an opportunity to shake up his strategy.
Here, we look at who could replace Longstaff to play alongside brother Matty – or how Bruce could alter his gameplan to unlock some desperately needed creativity.
When available, Hayden has been ever-present in Bruce’s side, missing three out of 10 Premier League games only through suspension following his sending-off in the drubbing at Leicester.
The former Arsenal man is the clear favourite to step in at the London Stadium.
But will that rash tackle on the Foxes’ Dennis Praet have dented Bruce’s confidence in his man, or will he look to use Hayden’s ability to drive forward from midfield rather than simply ask him to sit deep in midfield?
Ever the enigma, Shelvey played four of the first six league games of the season before dropping out of the side, with Bruce seemingly seeing him as a luxury United can’t afford.
The former England international returned to action on Sunday against Wolves, coming off the bench in the 85th minute – but only once Newcastle were short-handed in their engine room following Longstaff Sr’s dismissal.
But with Newcastle having not recorded a single shot on goal against Chelsea on their last London visit, is it time for Bruce to build his struggling midfield around Shelvey’s ability to play a killer pass?
Forgotten man Ki has only made one start in all competitions this season.
His only start came early in the season at Norwich City and he hasn’t even been in the matchday squad since the Leicester game at the end of September.
This leaves him as seemingly the least likely to replace Longstaff, but the South Korean tends to take care of the ball in a way which Bruce identified as a necessity following Sunday’s draw against Wolves.
Bruce’s back five has made The Magpies relatively solid at the back, but a return of six goals from 10 games – and none in their last 263 minutes of action on the road - is the second worst in the Premier League.
Newcastle have tended to opt for a safety-first 5-4-1, and have conceded 15 goals.
Could a 4-2-3-1 formation solve their problems?
This would get a midfielder higher up the pitch in an attacking midfield role which could be key to creating more chances for the isolated Joelinton.