The 20-year-old is currently knocking on Rafa Benitez’s door for a place on the bench against Chelsea.
Since Issac Hayden was sent off against Cardiff, Longstaff is keen to make his mark.
The midfielder, who starred in the recent 5-0 thrashing of rivals Sunderland for the U23s, almost left the club for Portsmouth and Rotherham on loan.
Last season, he was loaned out to League One Blackpool.
But it looks as though he could be in with a chance of making his mark for the Magpies this term.
In pre-season, Longstaff featured in all but one of the club’s five friendlies.
First team midfielder Diame certainly thinks highly of Longstaff.
The Senegal international believes he has what it takes to break into the first team.
He told the Journal, as quoted by Chronicle Live: “Sean is training very well and is a quality player – we can all see that.
“He can give good passes and in training he scores lots of goals. He’s a good player but needs to keep working.
“I think he is in the right hands with Rafa Benitez to do that.”
He does what in training?
With Diame divulging that Longstaff is a goalscorer in training, that surely has to make for encouraging news.
That, of course, was one of the biggest issues the team faced last season.
In 38 league games, the Toon Army only managed to score 39 goals.
At the moment, there is no real source (certainly in midfield) of goals, and that may be what encourages Benitez to give Longstaff a chance.
It will certainly be interesting to see Rafa’s teamsheet for Sunday’s game with Chelsea.
Hopefully Longstaff will have done enough to make the bench in Hayden’s absence.