Opponent Slugging Percentage OSLUG

OSLUG stands for opponent slugging percentage in baseball. Total bases opposing hitters averaged per at-bat against a pitcher — how hard they hit him, not just how often.

How OSLUG is calculated

OSLUG = total bases ÷ at-bats, counted against him

Home runs allowed drive it: a pitcher who gives up few hits but many over the fence posts a good average against and a poor OSLUG. The median pitcher with 100 innings allowed .403 in 2025.

What counts as a good OSLUG?

Half of the 324 qualified MLB players in 2026 were at or below .386. The best tenth were under .299.

Median: .386
Top 10% (low): .299
Leader: .194

By position, the median was .362 for RP and .407 for SP.

Qualified: 50+ IP, non-zero, 2026 regular season.