How long is the grace period that immunizes a player from criticism after that player contributes significantly to a championship?
Start from the answer to that question, then add the extension of time that same player would get for scoring the goal that pulled the championship out of an archrival's hands at the death, and the final answer is the degree of patience Sergio Aguero earned from Manchester City.
Aguero's moment came on May 13, 2012. Since then, Aguero has scored 47 goals for City in all competitions, including 30 this season.
And yet, Aguero's staggering productivity in the matches he does play only serves to underscore the hole he leaves in City's XI when he cannot. That happens all too frequently now given Aguero's troubled hamstrings, quadriceps, calves, etc.
City qualified for the knockout stage of the Champions League for the first time in the club's history this season and had Aguero on the pitch for one of the four halves they played against Barcelona.
City have had to get used to the intermittent nature of Aguero's ability to go. In 2012-13, Aguero started only 22 of City's 38 league matches and mustered only 12 goals in the league.
Such was Aguero's ineffectiveness last season that Edin Dzeko outscored him in the league despite making six fewer starts.
Sure, Aguero was incendiary early in the current season. To a significant degree, Aguero carried the Sky Blues through Champions League qualifying with matching braces in both the home and away legs against CSKA Moscow.
But Aguero missed almost exactly one month from the middle of December through the middle of January and then shortly thereafter was out for the entire month of February.
Now the Argentine is out again, though a eurosport.com report indicated recently that "manager Manuel Pellegrini has expressed hope the Argentina forward could be back in action within a fortnight and Aguero himself has also said the issue is not serious."
Aguero's inability to stay on the pitch has become a serious concern for City. Per Richard Farley of prosoccertalk.NBCSports.com:
There’ve been too many times where a minor problem turned into a major concern...a third leg injury of the season speaks to Aguero’s overall health. Either he’s been unlucky, has become unexpectedly injury prone, or is seeing issues cascade into new ailments.
Which begs the question: How long can this go on with Aguero for City?
Aguero recently signed an extension to his contract at the Etihad, which now runs through 2017.
Every player has a price.
City's rhetoric has not stopped Real Madrid from lurking in the shadows and broadly hinting at trying to pry Aguero out of Manchester anyway.
Per Tom Hopkinson of the Mirror, "(Carlo) Ancelotti has long been an admirer, however he knows City will not want to part with one of their most important players and he would face a real battle to prise the Argentinian from the Etihad."
Will Manchester City ever sell Sergio Aguero if he does not ask to leave?
Maybe. But if Aguero continues to pull up lame through the balance of City's Premier League title run, city boss Manuel Pellegrini might have to at least consider whether the ongoing "will he play or won't he" drama that has followed Aguero around for two seasons now fits into Pellegrini's vision for the club.
While it is true that none of Dzeko, Alvaro Negredo or Stevan Jovetic is the player that Aguero is—and that Jovetic has been a bigger injury headache than Aguero has this season—it is also true that City have a glut of strikers who might be able to replicate enough of Aguero's production.
Particularly if you're talking about half a season of Aguero's production.
Ultimately, this piece is not a call to sell Aguero. It is merely a reminder to never say never.
If City really have dreams of Champions League glory and Premier League dominance, their central defense must be fixed—and that will cost them plenty in transfer fees.
For what Real would likely be willing to pay for Aguero, City could buy a centre-back and probably a prime holding midfielder with the remainder.
Then again, if Aguero comes back from this latest trip to the physio's room and leads City on a thrilling charge to the Premier League title, we'll just pretend like this discussion never happened.