A former team-mate of Cristiano Ronaldo has delivered his verdict on the Portuguese legend potentially returning for a third spell at Manchester United. The 40-year-old has reportedly become unhappy at Al-Nassr, believing owners the Public Investment Fund (PIF) have favoured its other three teams ahead of his own. Ronaldo could seek a fresh move in the coming months as he targets hitting 1,000 career goals before he retires.Ronaldo became the highest-profile player to move to the lucrative Saudi Pro League in 2023 when he signed for Al-Nassr shortly after having his contract terminated at United. The Portugal international has continued to score goals at a prolific rate in the Middle East, though the only trophy he has picked up during his spell at the club so far has been the 2023 Arab Club Champions Cup.Al-Nassr are well placed in the Pro League title race this season, only trailing current table leaders Al-Hilal by a point after 19 games, but Ronaldo has reportedly felt let down of late after Saudi Arabia's Public Investment Fund decided to facilitate a transfer from Al-Ittihad to Al-Hilal for striker Karim Benzema, which Ronaldo feels has given his title rivals a boost in their pursuit of silverware when he and Al-Nassr should have been helped instead.Speculation is growing over Ronaldo's future, with some even mentioning the possibility of a third stint with Manchester United.The veteran forward became a world superstar during his first spell at Old Trafford, picking up a collection of trophies including the Premier League and the Champions League while also scooping his first Ballon d'Or.He continued his path towards all-time legendary status by moving to Real Madrid, for whom he became the club's all-time leading goal-scorer with 450 strikes in 438 appearances, before spending three seasons in Italy with Turin giants Juventus.Ole Gunnar Solskjaer brought Ronaldo back to United in 2021 as the Norwegian targeted a title push and his old team-mate repaid him with goals, registering 24 in 38 matches across all competitions. However, Solskjaer was sacked and replaced by Erik ten Hag, who struggled to see eye to eye with Ronaldo, resulting in an explosive departure to Al-Nassr.Now, former team-mate Wes Brown has given his take on a potential return to United for Ronaldo.Speaking to BettingLounge, Brown said: "He’s not happy but would Cristiano Ronaldo come back to Manchester United for a third go? I would say no. I can't see how that could happen. A move to MLS? Maybe. Maybe he goes back to Portugal and plays there. I’m sure he will still have so many options. "The main thing is that he still wants to play in the World Cup and we would have to keep playing and making sure he keeps himself fit to do that. It’s a shock to everyone to see Ronaldo on strike but I honestly think it will get resolved. We’ll have to wait and see where it goes from here."Add GOAL.com as a preferred source on Google to see more of our reportingWhoever United appoint as their next permanent manager in the summer, it would undoubtedly be more than just surprising if they were to make Ronaldo their number one transfer target. That said, it is thought there are still a number of options for the five-time Ballon d'Or winner to continue his club career, with teams in Major League Soccer and in Europe thought to be keeping an eye on developments.Ronaldo reportedly has a €50 million (£43m/$59m) release clause written into his Al-Nassr contract, meaning teams will be able to prise him away from the Riyadh-based club if they stump up the cash.As for on-field matters, it remains to be seen if Ronaldo will end his strike anytime soon. Al-Nassr are next in action against Al-Ittihad on Friday evening.