Ronaldo has been heavily criticised for failing to celebrate Gareth Bale’s opening goal - leading to accusations that the Portuguese superstar is obsessed with his own achievements - and these sentiments have been echoed by Stoichkov.
The great Bulgarian striker, who won the Ballon d’Or during his first spell at the Camp Nou, believes Ronaldo “committed suicide” as a teammate at the weekend and feels the time might be right for Los Blancos to cash-in on the former Manchester United star.
Stoichkov blasts Ronaldo
"You can never get angry because a team-mate has scored and not celebrating is to commit suicide as a team-mate because then you are worth nothing and you are worth nothing to your team," he told Sportium, according to Goal.com.
"You can't doubt the quality of either Ronaldo or Messi. Messi is where he should be and Cristiano is going through a difficult time but all players go through rough patches. I was whistled as well in my time. It's up to the coach to make decisions and to speak to the player.
"Maybe the obsession with Messi is affecting him but I'm not inside his head. Messi motivates his team-mates and, if Ronaldo doesn't score, it affects his team.
"At times like that you have to display your personality; 99 per cent of players can't answer the question 'why am I being booed?'
"Messi is at the level of Pele, Diego Maradona and Johan Cruyff and what annoys Cristiano is that he is only compared to Messi.
"You'd have to ask Florentino Perez about Ronaldo's future. Sooner or later, Cristiano will be sold by his president. The world of football is like that but it depends on his president.
"I don't know if they are short of money. If they are, it's a good moment to sell him."
Ronaldo has become too self-obsessed
This is not the first time a former player has suggested it might be time for Real Madrid to sell Ronaldo.
Just last month former Manchester United striker Terry Gibson also accused Ronaldo of being too self-obsessed and feels the Portuguese star is too preoccupied with scoring goals rather than doing what is most effective for his team.
Many would argue that Ronaldo is most effective when he is being selfish on the pitch; after all, this is a player who has scored a ridiculous 293 goals in 285 appearances since arriving at the Bernabeu in 2009.
But there was no excuse for his behaviour against Levante on Sunday. Bale was under intense scrutiny and pressure last week - and Ronaldo was acutely aware of this.
As a senior and influential member of the team, Ronaldo should have been the first one over to congratulate the Welshman, rather than throwing his arms around theatrically because his initial shot had been cleared off the line.
Messi pressure getting to Ronaldo
One suspects the fact Messi had overtaken Ronaldo in the race for the Pichichi a day earlier had a psychological impact on the Real Madrid No. 7.
Ronaldo is desperate to become the best player of all time - but in order for that to happen he will need to at least equal the number of Ballon d’Or awards secured by four-time winner Messi.
If Messi ends the season as La Liga’s top scorer - and helps Barcelona win silverware in the process - the Argentina international could win the prestigious individual accolade for a record-breaking fifth time.
At the age of 30, three-time Ballon d’Or winner Ronaldo only has a number couple of years at the very top, and it seems he is becoming increasingly anxious at the distinct possibility he will end his career known as merely the second best player of his generation - let alone the best player of all time.
Should Real Madrid consider selling Cristiano Ronaldo - or is it a crazy idea? Have your say in the comments below!