What is Left on Base (LOB) in Baseball?
Left on base (LOB) is a baseball statistic recording the number of runners who are on base when the third out is made — they "left" on base without scoring, making LOB a key measure of how well an offense converts opportunities into runs.
Left on base (LOB) is a baseball statistic that counts the number of runners who are still on base when the third out of a half-inning is recorded. Any runner who doesn't score and isn't retired in the field is "left on base" — stranded when the inning ends.
LOB is tracked for both individual batters and teams. It appears in every standard box score and is one of the most talked-about stats in any close game where a team fails to cash in on scoring opportunities.
Team LOB vs. Individual LOB
Team LOB: The total number of baserunners stranded across all innings. High team LOB typically signals an offense that gets runners on base but fails to bring them home — often through strikeouts in key situations, double plays, or a lack of clutch hitting.
Individual (batter) LOB: For a batter, LOB counts the total number of runners on base when they make an out. A batter who comes to the plate with two runners on and strikes out is charged with 2 LOB. This stat is closely tied to a hitter's performance "with runners in scoring position" (RISP).
LOB in a Box Score
A standard box score records team LOB in the summary line. You might see:
| Runs | Hits | Errors | Left on Base | |
|---|---|---|---|---|
| Visitors | 2 | 8 | 1 | 9 |
| Home | 4 | 7 | 0 | 6 |
Here, the visiting team got 8 hits but only scored 2 runs — and left 9 runners on base. The home team was more efficient, converting their opportunities into 4 runs with fewer stranded.
What LOB Tells You
A high LOB total isn't automatically bad. You have to consider:
- Hits and walks generated — If a team reaches base frequently, they'll naturally strand more runners. A team that gets 12 baserunners per game will leave more on base than one that gets 6.
- Timing of hits — A team can go 0-for-7 with runners in scoring position and have a high LOB despite solid overall hitting numbers.
- Opponent pitching — Strong relievers or an ace starter who limits damage will naturally inflate a team's LOB total.
Baseball analysts often use LOB% (left-on-base percentage, or strand rate) instead of raw LOB — it measures what percentage of baserunners a pitcher strands, and is part of evaluating pitching performance.
$$\text{LOB%} = \frac{H + BB + HBP - R}{H + BB + HBP - (1.4 \times HR)} \times 100$$
For pitchers, a high LOB% over a full season can indicate they're "pitching to the score" or getting lucky in high-leverage situations. An unsustainably high strand rate is a flag for regression.
LOB and Clutch Hitting
LOB is closely tied to performance with runners in scoring position (batting average with RISP). Teams or hitters who perform poorly in high-leverage spots accumulate high LOB totals. In a close game, stranding runners repeatedly is often the difference between winning and losing.
A common frustration in baseball broadcasts: "They left three men on in the third, two more in the sixth..." — all of that is LOB, and it typically explains why a team lost a low-scoring game despite getting on base.
LOB and OBP
Teams with high on-base percentage (OBP) tend to have higher raw LOB numbers — simply because they put more runners on base. This is why LOB alone doesn't tell you whether an offense is efficient. Context matters: a team with a .380 OBP leaving 8 runners on base is more efficient than a team with a .330 OBP doing the same.