To be clear, this isn't a question asking who Manchester United's best player is. That would simply be a choice between
Bebe Robin van Persie or Wayne Rooney. It is, though, a question asking who is the most indispensable player on the squad. Which player, if he were to be unavailable for an extended period of time, would be United's biggest loss? Which player's absence would most hinder the quest for trophies -- primarily the Premier League or Champions League?
Fortunately for United and their supporters, Sir Alex Ferguson has a strong squad at his disposal and one with adequate depth in nearly every position. Unlike the sport of baseball, where there are pretty advanced metrics that can accurately gauge a player's value to an extent, trying to decipher this is mostly a subjective exercise. That's not to say, though, that we can't come up with reasonable conclusions. For example, everyone of us can say with absolute 100% certainty that losing RvP would be much more detrimental than losing Federico Macheda (only Kiko's mother would argue otherwise... or maybe not).
Here's a list of candidates that I've proposed. Be sure to vote in the poll and feel free as well to offer your opinion in the comments section.
* Robin van Persie: The Dutchman and £24m summer signing from Arsenal is the reigning player of the year in the Premier League. He's also arguably the best player in England. If the world-class striker were to miss any games, United would undoubtedly be a worse team. Fortunately though, there is tremendous cover in the strike force: Rooney, Javier Hernandez (Chicharito), and Danny Welbeck.
* Wayne Rooney: The England international is certainly in the discussion as to who is the best player in the United squad and in the Premier League. The versatile Rooney can play as a false 9, a wide attacker, and as a central-midfielder. He's most effective, though, at the current moment as a No.10. When he's in an industrious mood, he can be world-class on his day. The recently acquired Shinji Kagawa is a fantastic No.10 as well and he perhaps could lessen the blow of any possible Rooney injury or dip in form.
* Michael Carrick: Fergie definitely sees Carrick as his midfield stalwart. Selection choices in midfield are usually based on complimenting the durable Englishman. The 31-year-old is a polarizing figure but to those who appreciate him as a player, they see him as the one that provides most stability in United's midfield. This is because of his responsible circulation of the ball and because of his tremendous positioning providing structure to the team's shape.
* Antonio Valencia: The right-winger hasn't been in stellar form this season but he's still been a vital contributor. By hugging the right touchline, Valencia provides an outlet in attack while he also horizontally stretches the attacking space. In addition, he forms a wonderful and balanced partnership with right-back Rafael. With Nani out due to injury and with his contract situation causing tension with the club at the moment, the Ecuadorian is United's only viable right-wing option. The other attacking options either tend to drift into more central roles (i.e. Rooney, Kagawa, Welbeck) or they're much more effective on the left-flank (i.e. Ashley Young, Ryan Giggs).
* Patrice Evra: The former world-class left-back might seem like an odd option but it could be argued that he has the least adequate cover out of the first-choice players. Alexander Buttner had a wonderful debut versus Wigan Athletic but he's looked shaky at other times. Truth be told, we don't know much about the 23-year-old Dutchman. Evra's form has dramatically improved this season as he hasn't been the liability that he's been in recent seasons. If anything, he's been a strength.