This is really a tough question because of all the circumstances!
Some are taking the quesion the wrong way I believe & thinking that the lazies sports-players are simply those who play a sport which doesn't require much of an effort or movement, such as bowling or darts as some mentioned above.
Are we talking DROP OFF in production or effort which would be different for each sport?
For example, some of you say the laziest players are in the NBA, but when you think about it, it's almost impossile to ever be lazy when they're out there on that court because regarldless of the score, etc. they are still having to put out much more effort at all times than almost every other sport. They are constantly on the move, even if sometimes it is a little slower than other times.
So can they still be considered the laziest when you compare their "lazieness" period which is still a lot of work vs other sports?
How about MLB players who sit in the dugout and watch while their teammates bat half of the game, and go up to bat 3-4 times a game, and stand in the field waiting on the ball to get hit to them every once in a while.......