Look at the top flight players during the winter months and you will see a lot of them are wearing base layers. Gareth Bale, Wayne Rooney and Robin Van Persie all wear them. They are not just wearing them for show, there is proven performance improvements associated with wearing football base layers.
RVP Baselayer
Wearing a tight fitting base layer will reduce muscle osculation and keeps muscles in line. This helps to prevent injury and promotes energy savings.
Compression is a tried and tested medical treatment that has been used to treat muscle injuries for many years. This is now being used in a sports environment with compression garments and base layers. These products are designed to improve blood flow which improves oxygen delivery. This in turn helps to reduce muscle fatigue potentially allowing a footballer to play longer and train harder.
The material used in base layers wick away sweat. In cold weather this ensures that there is no moisture against the skin giving the wearer an uncomfortable cold feeling. This means that a player does not waste valuable energy keeping warm.
In hot weather a footballer can sweat up to a kilo of fluids during 90 minutes of football. The wicking material used in compression and baselayer garments ensures that a player in not carrying this weight around during the game.
Following training or match play compression wear can be worn to reduce soreness caused by muscle vibration and speed up recovery times. A player can return to training up to 24 hours earlier.

Players will ultimately question the cost of some of these items. Base layer tops range from £20 to £30 and compression tops £35 to £75. However the garments are a quality product that will last a season or two for the average player. The same player would probably have no qualms about spending that amount of money filling the tank of their car. People are often reluctant to spend money looking after themselves.

All of the benefits enjoyed by the top flight players can be enjoyed by all, right down to park players. The tight fitting compression garments are particularly useful as amateurs are not always at their peak. The reduction in muscle vibration will help prevent soreness, players becoming tired and injuries resulting from this.
Whilst you may be slightly embarrassed by these figure hugging garments in the changing room the added benefit they bring are certainly worth it.