I came across this chart. I have no idea if it's relevant:
This is all based on time spent on DL relative to age/position. I don't know why CF or 3B isn't included.
This graph comports more with the conventional wisdom: SS, 2B, and P all rise in injury risk rapidly, while corner outfielders (cOF) are more or less flat over time (corner outfield being a not very demanding position). There’s also some weird patterns though–why does 1B increase much more rapidly than even the SS/2B/P combination? Why does catcher (C) injury risk decline over time? Part of the problem, I suspect, is that players’ positions are not static over time. Often, players who are injured at catcher are switched to first base (Joe Mauer being a recent example); which movement can be viewed as exporting aged catcher’s injury risk into the 1B category. This “position effect” could result in all the older catchers who stick around at C being hardened, un-injurable veterans; if they weren’t, they would have switched positions.
Position effect is a subset of a larger class of effect which I’ll term survivor bias. Consider shortstops: notice that there’s missing data already at age 32 or so–simply because few shortstops play when they are that old! What’s more, the SS who remain playing into their mid-30s are unlikely to represent a random sample of all shortstops. To say it differently, older players have very different characteristics from younger players, because younger players who didn’t have those characteristics were removed from the sample. Statistically, this type of bias, called “Missing Not at Random,” is among the most pernicious and troublesome issues.
This is all based on time spent on DL relative to age/position. I don't know why CF or 3B isn't included.