If you're getting into MLB betting — especially player props — you're going to see a lot of acronyms thrown around. ERA, WHIP, OPS, wOBA, FIP, BABIP. It can feel like a foreign language at first, but you don't need a statistics degree to use these numbers effectively. You just need to understand what each one actually tells you and why it matters when you're deciding where to put your money.
This guide covers the stats that are most relevant to betting. We'll skip the ones that look impressive on a broadcast but don't actually help you make better picks.
Pitching Stats
The average number of earned runs a pitcher allows per nine innings. An ERA under 3.00 is excellent, 3.00 to 4.00 is solid, and anything above 5.00 means the pitcher is getting hit hard on a regular basis.
ERA is the most commonly cited pitching stat, and it's a decent starting point for gauging how a pitcher has performed. The limitation is that it can be influenced by luck, defense, and sequencing — a pitcher might have a low ERA despite mediocre stuff if their defense has been saving them, or a high ERA despite good peripherals if they've been unlucky with timing of hits.
WHIP measures how many baserunners a pitcher allows per inning. A WHIP of 1.00 is elite — roughly one baserunner per inning. Above 1.30 is below average, and above 1.50 means constant traffic on the basepaths.
For prop bettors, WHIP is arguably more useful than ERA because it directly indicates how many opportunities opposing hitters have. A high-WHIP pitcher creates more RBI chances for the middle of the opposing lineup. When you're evaluating H+R+RBI props, look at the opposing pitcher's WHIP first.
How many batters a pitcher strikes out per nine innings of work. A K/9 above 9.0 is considered high-strikeout territory. Below 6.0 means the pitcher relies on contact management rather than missing bats.
High-K pitchers are generally tougher matchups for hitter props because they reduce the number of balls in play. But K/9 needs to be read alongside BB/9 — a pitcher who strikes out a lot but also walks a lot can still create scoring opportunities through those free passes.
The number of walks a pitcher issues per nine innings. Below 2.0 is excellent control, 2.0 to 3.0 is average, and above 4.0 is a problem. Walks put free baserunners on, which inflates WHIP and creates RBI opportunities without the batter having to do anything.
This is one of the most underrated stats for betting purposes. A pitcher with a high walk rate is essentially giving away free baserunners, which boosts the value of hitter prop overs for the batters behind those walks in the lineup.
FIP estimates what a pitcher's ERA should be based only on the things the pitcher controls directly: strikeouts, walks, hit-by-pitches, and home runs. It strips out defense and luck on balls in play.
When a pitcher's ERA is significantly lower than their FIP, it suggests they've been getting lucky and might regress. When their ERA is much higher than their FIP, they might be better than their results indicate. This gap is one of the most reliable indicators of future performance changes — and future line movement.
Hitting Stats
OPS combines on-base percentage (how often a batter reaches base) with slugging percentage (the total bases a batter averages per at-bat). An OPS above .800 is good, above .900 is excellent, and above 1.000 is elite.
OPS gives you a quick snapshot of a hitter's overall offensive production. For H+R+RBI props, a high OPS is a good baseline indicator because it means the hitter is both reaching base frequently (contributing to hits and runs) and hitting for power (contributing to RBI).
wOBA is a more refined version of OPS that properly weights each type of offensive event (single, double, triple, home run, walk) based on its actual run value. The scale is similar to on-base percentage — .320 is average, .370 is excellent, .400 and above is elite.
Many serious bettors prefer wOBA over OPS because it's a more accurate measure of offensive contribution. When comparing two hitters for prop plays, wOBA gives you a cleaner comparison. You can find wOBA on Baseball Savant and FanGraphs.
This measures how often a batter hits the ball hard (95+ mph exit velocity). The league average is around 35-40%. Hitters above 45% are making consistently hard contact, which correlates strongly with future offensive production.
Hard hit rate is one of the best indicators of a hitter's true quality because it's not affected by luck or defense. A hitter with a low batting average but a high hard hit rate is probably getting unlucky and due for a correction upward — making their prop line potentially undervalued.
The batting average on all balls that are put into play (excluding home runs, strikeouts, and walks). The league average BABIP is around .300. Hitters with a BABIP significantly above .300 may be running hot, while hitters well below .300 may be running cold.
BABIP is one of the best tools for identifying hitters whose stats are about to shift. A good hitter with a .220 BABIP is almost certainly going to see their batting average climb. A mediocre hitter with a .370 BABIP is likely to cool off. Use BABIP to identify players whose current stat lines don't reflect their true talent level.
Which Stats Matter Most for Prop Betting?
If you're focused on H+R+RBI props, here's a prioritized checklist of what to look at. For the opposing pitcher, check WHIP and BB/9 first — these tell you how much traffic will be on the bases. Then check FIP versus ERA to see if the pitcher is likely to get better or worse. For the hitter, look at wOBA or OPS as a baseline for overall quality. Then check hard hit rate and BABIP to see if they're running hot, cold, or right around expectation.
You don't need to memorize every advanced stat in the book. A handful of well-understood metrics, used consistently, will put you ahead of the vast majority of bettors who are still making decisions based on batting average and win-loss record.
Check out our projections page for today's top hitter matchups with opposing pitcher stats factored in. It's designed to give you the quick-reference data you need to start your daily analysis.