How to keep my son interested in baseball after an all loss season?

My sons Little League season has been less than awesome. In fact they have lost every game this season thus so for. Sadly, my son gets discouraged easily and insist he is not intrested in baseball no longer and doesn't want to play in next season. To me this sounds strange as before he LOVED baseball, for the past three years in fact, and all of those prior years he has been on a great team, one being undefeated. Should I let him give up, or keep insisting that their will be good years and bad years. My kids are generally raised to be not quitters, so it's tough.