Your points are well taken. Does that mean that a percent, rather than total, of RBI's -- vs. left on base -- (1) with runners in scoring position and (2) with runners on base would be a better indicator of the value of, particularly, a middle of the order hitter?
Not how often he drives runners in, but rather what percent of the possibilities.
Imagine trying to recreate those stats.
Yes, a percentage stat would be much better than a raw number. After all, we recognize that the guy with the higher avg wins the batting crown, not the one with the most hits. Baseball Prospectus attempts to define this with OBI% (Others Batted In).
As Phrazbit stated, RBI are an opportunity stat. Typically, we can assume that two guys with the same stat line and drastic RBI number differences is fully explained by their teammates hitting in front of them. There is situational performance fluctuation year-to-year, but that would wash out over a career.
So how did Mark Trumbo get his 2012/2013 RBI totals? Well in 2012 he hit behind Mike Trout (.399 OBP), Torii Hunter (.365 OBP), and Albert Pujols (.343 OBP), which gave him 159 PAs with RISP (27% of his total PAs) and 282 PA with ROB (45% of total PAs). When you come up almost half the time with a guy on, you're gonna knock them in if you can put wood on leather.
In 2013 Pujols had a bad year, but Mike Trout put up a .432(!) OBP. --Hack Wilson's 191 RBI season included two players ahead of him putting up OBP above .420-- which gave Trumbo 162 PA with RISP (29% of total PA) and 314 PA with ROB (51% of total PAs).
Trumbo had a MUCH more productive 2012 than 2013, but his RBI total was less. Well there were less total PAs in 2012, but also less RBI opportunity situations as well that caused this.
Given the facts that, outside of the steroid era, players peak at age 27, that Trumbo was arbitration eligible and set to make much more money, that the players ahead of him in the lineup heavily contributed to his perceived value (he did hit those HR on his own), and finally that he didn't have a defensively critical position to play, it makes perfect sense why LAA would shop him this past offseason. He's set to become more expensive, less productive, and his production is potentially over-valued by other clubs in the league (like our club). LAA has seen no drop off in team RS/G this year (4.70) compared to the last two Trumbo RBI years (4.73 2012, 4.52 2013) because his real contribution wasn't really that great and they were able to replace it.
