As such, every offensive stat is subject to circumstance.
An example used in this thread is RISP. Obviously, for a given plate appearance to even qualify to be calculated into this analysis, there must be at least one runner in scoring position. (Out of the player's control.) Since we're talking percentages (BA, OPS, etc.) rather than aggregate, that doesn't really taint the analysis. However, the situation, or the circumstances most certainly influence the potential outcome, and the most common stats do not consider circumstance. (only very specialized stats do, and they are not used in formulas that calculate standard analyses like BA or saber ones like WAR.
For example, does RISP recognize the difference between situation A: a runner on second with 2 outs in a 10-0 game vs. situation B: runners on second and third with 0 outs in a tie game in the bottom of the last?
Does anyone disagree that the defensive approach (fielding positioning and pitching) is different in each situation, and that the likelihood of producing a positive offensive outcome is greater in B than in A? If not, how can RISP really be used as a comparable analysis when there are variables at play almost every time?
To be clear, I am a fan of statistics. I think there is value in standard and saber stats, although I'm admittedly a skeptic on the usefulness of certain ones (both standard and saber.)
However, I am firmly in the camp that logic suggests there is so much more to analyzing a player than either set of stats is capable of doing.
Pulling this all together to make it relevant to the topic of Jay Bruce, I think we all know he is the classic streaky hitter. It seems that he is either on fire or cold as ice. We never know how long the hot streaks will last, or when he will catch fire from a cold one. We just know they're going to happen until he proves otherwise.
So yes, as of late, including last night, he looks like a "professional hitter." I don't need to glance at his OPS with RISP to confirm whether he is or not, because unless he begins to deviate from his norm, his OPS will most certainly drop as soon as his next cold front moves through, and then it shall soar again as if he were a human sine curve.
Other players may not be as streaky, but baseball will always be circumstantial. Until those circumstances are built into formulas to create a more accurate analysis of production, stats will always be subject to, "yeah, but..."