Joey Barton has demanded that Newcastle's hierarchy reinvest the money received from the sale of Andy Carroll in order to help the club challenge for Europe.
Liverpool paid £35million for England striker Carroll on January transfer deadline day after the 22-year-old's emergence as a star in the making.
The loss of the 11-goal forward has been viewed as a major setback for Newcastle and Barton is frustrated by the sale.
But the in-form midfielder, who helped the club move up to ninth in the Premier League with Tuesday's win at Birmingham, thinks there is an opportunity if the profits are spent wisely by club owner Mike Ashley.
Barton said: "As soon as we get something going, players get sold and then we have to start again.
"It feels like it's a constant work-in-progress and it is tough in that respect, although we have character and spirit in abundance.
"We've got some good players in there and, if we can add more to that in the summer, then we've got the basis, a spine of a top side and a side that is capable of challenging for Europe, in my opinion."
Barton thinks that Newcastle need to add between five and seven top-quality players to their Premier League squad.
He added: "We need a squad to compete on all fronts and we want to do that.
"That's up to the men upstairs to make sure we amass a squad and get the bodies in to challenge for Europe.
"You need to spend money. If you pay peanuts you get monkeys so hopefully they spend it (the Carroll money) and spend it wisely.
"We've probably got 15-16 Premier League-quality players with that experience, but I think you need 20-22 to really compete at the top end."