Projecting Stolen Bases Using SBO% and Success Rate
Last year there were many disappointments in the stolen bases department: Michael Bourn, Elvis Andrus, Erick Aybar, Alex Gordon, Aaron Hill, Austin Jackson, and Cameron Maybin.
All of these players have one thing in common as the reason for their declined success on the base-paths – a decreased stolen base opportunity percentage.
| Player | Year | AB | Stolen Bases | OBP | SBO% | SB Success % |
| Michael Bourn | 2011 | 656 | 61 | .347 | 38% | 81% |
| 2012 | 624 | 42 | .347 | 28% | 76% | |
| Elvis Andrus | 2011 | 587 | 37 | .342 | 26% | 76% |
| 2012 | 629 | 21 | .345 | 16% | 68% | |
| Erick Aybar | 2011 | 556 | 30 | .317 | 27% | 83% |
| 2012 | 517 | 20 | .319 | 19% | 83% | |
| Alex Gordon | 2011 | 611 | 17 | .372 | 14% | 68% |
| 2012 | 642 | 10 | .366 | 8% | 67% | |
| Aaron Hill | 2011 | 520 | 21 | .294 | 22% | 75% |
| 2012 | 609 | 14 | .357 | 12% | 74% | |
| Austin Jackson | 2011 | 591 | 22 | .314 | 17% | 81% |
| 2012 | 543 | 12 | .377 | 12% | 57% | |
| Cameron Maybin | 2011 | 516 | 40 | .321 | 35% | 83% |
| 2012 | 507 | 26 | .303 | 25% | 79% |
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As you can see, all of these players have one thing in common as the reason for their declined success on the base-paths – a decreased stolen base opportunity percentage. In fact, it’s almost a case lesson on the subject when looking at the production of Andrus, Bourn, and Aybar, all of whom nearly matched their at bat totals (in Andrus’ case they increased), their OBP’s were near identical to their OBP of the previous season, and yet we see the marked decline in stolen base totals.
Stolen Base Opportunity Percentage is a metric designed by Baseball HQ to accurately describe how often a runner is given the “green light” to steal. It is calculated by the formula:
(SB+CS) / (BB+ Singles)
During the evaluation process of past stolen base performance fluctuations, there is little doubt that SBO% plays an immense role in a player’s stolen base production.
Not to be outdone, however, is of course the On Base Percentage statistic – this plagues a vast majority of the leagues speedsters. As the saying goes, “You can’t steal first base.” Some of these speedsters can still accumulate massive stolen base totals in limited at bats despite poor on base skills. There are a few of these players that come into the 2013 MLB Season as sleepers due to possible avenues for falling into playing time.
Emilio Bonifacio – 2B/OF – Toronto Blue Jays:
2011 stats below:
| 565 AB | 40 SB | .362 OBP | 140 Spd Score | 27% SBO | 78% Success Rate |
Bonifacio suffered from some bad luck last year in regards to his line drive rate. But some of his other skills improved dramatically. His contact rate improved to 79%, and he flashed an 11% walk rate in 149 first half at bats. Furthermore, he stole bases at a 91% success rate, and given his increased speed score to 169, that’s a legitimate increase.
Here are his dare to dream statistics if his skills align perfectly:
37% On Base percentage in 600 Plate Appearances (NOT AT BATS) = 222 times on base. 41% stolen base opportunity rate in 2012 leads to this calculation: (let’s regress stolen base opportunity percentage to 36% just for slightly more accurate forecasting)
222 * .36 = 79.6 Stolen Base Opportunities (let’s round down to 70 since he rarely hits anything more than singles and doubles, but will steal 3rd base more often than most).
70 Stolen Base Opportunities * 87% Success rate (though I think he can maintain a higher one) = 60.9
The calculation process yields 60 SB for Bonifacio. Believe it or not, this is absolutely reasonable.
Here are some other players and their output, should they also receive 600 plate appearances (these will be based on my projected OBP, Spd Score, SBO%, and SB Success Rate that will be calculated roughly based on past performance and future performance prognostication). Average Position Rank will be based off FantasyPros.com consensus position rankings that are compiled by all expert consensus rankings.
| Player | Team | Pos. | AvPosRnk | SB Proj | OBP Proj | SBO% Proj | SB Suc % |
| Juan Pierre | Marlins | OF | 67th | 57 SB | .338 | 40% | 78% |
| Jean Segura | Brewers | SS | 21st | 44 SB | .323 | 33% | 74% |
| Eduardo Nunez | Yankees | SS | 28th | 45 SB | .300 | 40% | 83% |
| Carlos Gomez | Brewers | OF | 34th | 55 SB | .290 | 45% | 88% |
Caveats and Notes on this exercise:
- In 2011, Juan Pierre amassed 734 plate appearances, logged 68 SB with a .322 OBP, with a 43% SBO, and 79% Success Rate.
- Eduardo Nunez has never stolen more than 23 bases in a season, however, he has rarely been healthy.
- Eduardo Nunez plays horrible defense and is very unlikely to amass 600 PA, but the Yankees have been ravaged by injuries, and desperate times call for desperate measures.
- Carlos Gomez will hit around 15-20 HR’s, so his SB projection might be slightly inflated; although I did adjust it for extra base hits to some degree, but probably not enough.
- Carlos Gomez had a 54% SBO in the 2nd half last year with a 91% success rate in 275 AT BATS (not plate appearances) and amassed 29 stolen bases.
- These projections are obviously all on the high end for performance for each of these 4 players.
- These are bold predictions as well as calculations.
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The Author
