Solskjaer had hoped to bring in a number of signings ahead of next season, with a need for added depth in defence and midfield.
Manchester United striker Romelu Lukaku has been heavily linked with a move to Inter Milan this summer.
Longstaff is being targeted after a promising campaign with Newcastle last term.
Manchester United kick off pre-season against Perth Glory on July 13th, and then play the likes of Leeds United, Tottenham, Inter Milan and AC Milan.
However, Pogba is taking part in United's pre-season duties in Australia and latest reports suggest he is unwilling to damage his relationship with the club by trying to force them into a sale.
But a move for Longstaff hasn't materialised, with Newcastle playing hardball over the fee.
Pogba needs to boss and lead the team on the pitch, while also showing the United fans that he wants to help the team get back to their best.
To make matters worse - in my eyes - Los Blancos will likely have to sacrifice at least two big name players like Isco or Gareth Bale, to even consider being able to sign Pogba.
The Belgian is now on tour with Solskjaer's squad in Australia and United are set to face Inter in Shanghai on July 20.
However Sky Sport Italia have insisted that those behind the scenes at United have started looking at potential replacements, and have put Milinkovic-Savic at the top of their hit-list.
Moratella feels Pogba is a "very good player" who would be sold for a "galactico" price.