Well, my advice isn't going to be terribly helpful (probably just complicating things even more) but I say never keep a disruptive player unless he is so amazingly good that you can live with his horrible disposition and you have a team full of leaders and you win, win, win. Me, I won't tolerate a disruptive player even when all of those things are true.
But- I also say stay well clear of fragile pitchers. Fragile position players one can live with generally (at least for awhile, if they are great players) but fragile pitchers are just too great a risk. (Having said that, my Denver Brewers had a team captain starting pitcher who was fragile for years and mostly only suffered minor day-to-day injuries and was quite valuable to the team until he crossed the threshold into his 30's and started to have more serious arm injuries and turned into a Wrecked pitcher and now I've bought out the last year of his contract. Fare thee well, Matt Helm.) So you just never know.
