When is a base stolen?
Stolen bases generally start when a pitcher is throwing a pitch. However, they can start when the pitcher attempts a pickoff, or when the catcher throws the ball back to the pitcher. David Peralta stole home when the Rockies’ catcher lobbed the ball back to the pitcher.
Safely advancing to the next base is not always scored as a stolen base. Exceptions are:
- Wild pitches and passed balls unless he was attempting steal as the ball left the pitchers hand.
- An error by the opposing team led to the advanced base.
- Defensive indifference (they don’t want to risk a wild throw to second or their lead is so large it does not matter).
- In a double steals, if one runner is out, the other cannot be credited with a stolen base.
What summary statistics did I find?
Stolen Base opportunities per PA (SBO%). How often did the player have a chance to steal second base? This statistic only applies to stealing second base. It was calculated by number of times on first base (hits, walks, hit-by-pitch, and pinch runner) divided by plate appearances. Through 17 April, Locastro career SBO% was 30.1%.
Stolen Base Attempt percent (SBA%). When the player was on first base, how frequently did he attempt to steal second base? It was calculated by stolen base attempts divided by number of times on first base (hits, walks, hit-by-pitch, and pinch runner). Through 17 April, Locastro’s career SBA% was 23.8%.
Stolen base percent (SB%). While the previous statistics apply to opportunities and frequency of attempts, this statistic measures effectiveness - the most important measure. It was calculated by successful stolen bases divided by stolen base attempts. Through 17 April, Locastro’s career SB% was 96.7%.
In 2007, this Hardball Times article provided ranges of scores for SBO%, SBA%, and SB% for batters with at least 10 steal attempts and with a success rate of at least 88%. Let’s compare Locastro’s statistics to the ranges achieved by these elite base stealers.
- Locastro’s 30.1 SBO% was near the top of the range of 23.1% to 34.6%.
- Locastro’s 23.8 SBA% was in the middle of the range of 10% to 51% (51% was former Diamondback Eric Byrnes).
- Locastro’s 96.7 SB% was above the top of the range of 88.1% to 95.6%. Locastro is awesome!
What statistics shed light on Tim Locastro’s success?
Tim Locastro primarily stole bases off the pitcher.
Two reasons that is true follow:
- Locastro stole twice against Scott Oberg and Zac Davies, each time with a different catcher. That indicates the bases were more likely stolen off the pitcher than the catcher.
- All pitchers who suffered his stolen bases had a Stolen-Bases-Defensive-Runs-Saved (from The Fielding Bible) of zero or negative in the applicable season. Zack Davies was the only exception and my guess is Zack Davies was hampered by an injured. Zack Davies went on the injured list with back spasms in August 2019. Locastro stole a base off him twice – once two-weeks-before and once one-week-after.
The following chart provides information about circumstances when Locastro stole each base.
Teams outside the NL West were vulnerable.
Although from 2017 through 17 April, 49% of the Dback games were against NL West teams, only 43% of Locastro’s attempts against NL West teams. In games against teams outside the NL West, Locastro was about 26% more likely to steal a base.
The following list shows how often Locastro attempted to steal against each team.
- 6 Dodgers, Locastro’s former team
- 5 Rockies
- 4 Reds
- 3 Mets
- 2 Athletics, Braves, Brewers, Rangers
- 1 Cardinals, Dbacks, Nationals, Padres
Locastro stole more often in late innings.
57% of Locastro’s attempts to steal a base were in the 7th, 8th, or 9th inning. The following list shows how often Locastro attempted to steal in each inning.
- 7 Ninth inning
- 6 Eighth inning
- 4 Seventh inning
- 3 Sixth & third innings
- 2 First, second, & fourth innings
- 1 Extra innings
- 0 Fifth inning
At the point in the game when Locastro stole a base, 63% of the attempts occurred in close games when the score was within 2 runs.
The breakdown of how close the score was when Locastro attempted a steal follows:
- 9 tied
- 4 one run
- 6 two runs
An off-day increased the chances of a stolen base. 63% of Locastro’s stolen base attempts were on his first or second day back following an off-day. Although it could be argued that Locastro was more rested, my guess is that Locastro spent the off-day watching videos to find opportunities to steal bases.
- 11 First day back
- 8 Second day back
- 5 Third day back
- 6 Fourth or more
Intangible Benefits of stolen bases are huge.
Much has been written about calculating the tangible benefits of stealing bases (increased probability of scoring runs on successful steals minus losses from caught stealing). And many times a successful steal makes no difference on whether a runner actually crosses home plate.
Underappreciated is the huge impact of intangibles. Having an accomplished base stealer on first bases often messes up the pitcher’s mental process. And I believe that impact definitely helps the batter.
Let’s look at how Diamondback batters fared when Tim Locastro was on first base. Approximations of successful PAs (aka PAs with impact) with Locastro on base are .370 with no other baserunners, and .414 with one other baserunner. The percentage of PAs with impact compared favorably to the Diamondbacks’ recent season averages for OBP (.325 in 2019, .312 in 2020, and .327 in 2021 through 22 April). An additional intangible benefit was that many times not reaching base nevertheless led to a baserunner advancing.
The data shown in the following chart was manually (tediously) found in play-by-play data - corrections are welcome in the comment section.
Another important intangible benefit extends to motivating Tim Locastro who will help the Diamondbacks the entire season and beyond. Having his cleats in the Hall of Fame has likely provided Tim Locastro a strong and enduring motivation to play his best. One of the world’s great thinkers best summarized the idea in the following.
“The point is that Davey [Davey Johnson, Manager of Nationals 2011-2013] fully appreciates the importance of making decisions based on factual evidence and rigorous analysis. He strikes the right balance between relying on the tangible (data) and the intangible (confidence and motivation) and shows the rare ability of being able to make the right trade-off between winning the day’s game and motivating a player who will help the team win in the long run.” — opinion piece in The Wall Street Journal by Ben Bernanke, Federal Reserve Chairman 2006-2014