Selfishness

The other day I had an argument with my roommate about my favourite cricketer and does he really deserve whatever that has been bestowed upon him. There was an accusation that he is selfish and doesn't play for his country. I am not going to write defending him and saying blah blah....
The one thing stuck me was within a team what would be the most important factor that would motivate an individual to perform... To put it in simple words what could be the motivating factor for an individual to perform in a team.Can anyone just accept the fact they will have to work for the fullfilment of common team objectives without being selfish enough to think about their growth ? I for one personally believe that selfish is too harsh a word ... Is that's what all game theory about?
Everyone has to be mature enough to understand every member in the team has the right to being selfish till the time it doesn't contradict with the teams objective... I for one believe that one will not put all their efforts just to make sure that the team succeeds. I think it's the other way around. The team succeeds because it contains individuals who strive for individual success. Ofcourse it shouldn't contradict with the teams objectives and also the individual should be mature enough to give space for others to perform as well. To rephrase it , that individual should respect others right to perform brilliantly .... Confusing right ?
I have worked with some highly motivated individuals. I have even thought as to what make them tick? What makes them to perform brilliantly? Is it just the sheer fact they want their team to be the best or their company to be the best? It's difficult for me to imagine that way... There should be a atleast a very small intention in his mind which strives for individual brilliance.
Is that what we label as selfishness ?