Affect a player's performance? Now, I am not referring to the reading of the riot act to a recalcitrant but talented player (an asif being torn another one by a person like imran would be the exemplar), but am referring to the affect of the role of captaincy on the captain's own performance/form.
Some players arguably thrive on the 'added(?)' responsibility of captaincy (Lara, Smith, Imran while others seem to baulk at the onerous honour, and let it affect their form (Tendulkar). (Of course, the affect of coincidences and the timing aspect of things - players often becoming captains when past their peak etc. should not be ruled out....)
Personally, I don't think that captaincy and suchlike completely intangible attributes should be taken into account while considering the worth of a cricketer. What do u think?