Factors such as friendship, transfer fees, reputation, sponsorship deals or international team aspirations should not even come into it. If a player is performing well, they are in the team. If they are not, they should be warming the bench.
Sadly, that is not always the case in football, and it is not limited to Villa. Managers clearly have their favourite players and will, despite supporter criticism, play them.
As much as there are players that get into the team when they have not been performing, there are equally players that cannot get into the team despite being better that their counterparts.
There are numerous examples of players being in and out of favour with managers, but is it really the way it should be done? Take Ireland for example: a favourite of Mark Hughes but clearly disliked by Mancini. Warnock- O'Neill's golden boys, but quickly incurred Houllier's wrath and ended up in the reserves.
Those are just two of many examples, but it indicates that managers do have their favourites, or players they just don't like. It must be very difficult for players that are not liked by the manager, because their chances of first team football are remote. For example, if Houllier was still at Villa then Warnock would most certainly not be in the first team.
The tendency to choose players based on 'other' factors is prevalent. Albrighton was a sensation last season, only to be completely sidelined by McLeish when he brought in N'Zogbia. Of course, you want to use a big money signing, but the undeserved perseverence with Zogs in the early stages of the season have had an impact on Albrighton's confidence.
In the most part, the team selections are based on form, but there are other factors that influence a manager's decision. It may explain why certain managers seek out their old players when they move to a new club. Would any Villa supporter bet against Heskey moving to Sunderland in the summer?
It is a factor that is unlikely to change. Like everything else, people will always have their favourites. But, when so much money is at stake, is it right that players are chosen on things other than how well they play for the team?