Got any statistics or anything at all to back that up, or are you just talking out of your butt?
I can't think of a team sport position that has fewer sudden starts and stops than a baseball outfielder.
Statistics? No. Common sense? Yes. Constant was the wrong word on my part, sorry, but you kind of proved my point with your second statement. An outfielder is standing around letting his muscles cool down for an extended amount of time. Then all of a sudden he has to make quick explosive, movements such as sprinting and throwing. Which puts you at greater risk for strains, pulls, tears, ect.. In football, basketball, soccer, ect. you're moving around more so your muscles stay loose and warm.