MLB Quality Start Predictions Today: Per-Pitcher P(QS) for Fantasy (2026)

The league-wide Quality Start rate in recent seasons is approximately 36% of all MLB starts. That means roughly 6 in 10 starts do not clear the 6-inning, 3-earned-run threshold — even across an entire league of professional starters. The variance on any individual start is enormous: a pitcher who projects as a strong QS candidate will fail to record one in nearly half his starts on average.

Another data point: teams that receive a Quality Start win approximately 69% of the time — meaning a QS is a meaningful game-outcome predictor, not just a counting-stat checkbox. In leagues where QS replaces Wins as a category, the stat does exactly what its proponents argue: it rewards pitchers who pitch well and gives fantasy managers a more predictable category to manage.

This is the definition our model targets and what the P(QS) output on the /pitcher-quality-starts page predicts. If your league uses the standard definition, the probability output maps directly to your scoring category.

Several variants tighten the standard definition. The most commonly discussed is the “High Quality Start” or QS+, which requires 7+ innings pitched with 3 or fewer earned runs (maximum ERA of 3.86). This is associated with what some call the “Nolan Ryan threshold” in advanced fantasy circles, and FanGraphs and Pitcher List both reference it when discussing ace-level performances.

A second stricter variant is the “Plus Start”: the pitcher must complete 6 innings, but only qualifies with 0–2 ER in a 6-inning start (eliminating the borderline 6 IP / 3 ER performance), OR any start of 7+ innings with 3 or fewer ER.

Our model does not publish a separate QS+ probability, but the threshold can be approximated: filter for the top confidence tier (70%+ P(QS)) to identify pitchers most likely to clear a stricter quality threshold. Pitchers in the 70%+ tier are the ones whose recent form, IP depth trend, and matchup context all point toward a deep, clean outing — not just a barely-qualifying 6-inning, 3-run performance.

Since 2018, some MLB teams have used an opener — a reliever who pitches the first inning before a “bulk” pitcher takes over. In games where an opener is deployed, the bulk pitcher is mathematically ineligible for a Quality Start regardless of how well he pitches, because the inning counter starts at zero when he enters. He can throw 7 scoreless innings and record nothing in the QS column.

This is a real friction point for 6x6 league managers. The practical implication: before streaming a pitcher, verify he is the confirmed starter rather than the bulk arm in an opener game. Our /pitcher-quality-starts page only displays probabilities for pitchers confirmed as starting pitchers for tonight's game.

Consider a pitcher who throws 6 innings exactly, allowing 1 earned run and recording 7 strikeouts, with his team winning. This is a clear Quality Start. Here is what that outing is worth across the three points-scoring platforms where the math differs most:

The takeaway: for ESPN and Yahoo points players, QS probability is still a valuable depth signal — a starter who clears the QS threshold has pitched 6 innings, generating 18 IP points before a single strikeout. But for CBS and Fantrax points players, QS is a real dollar-value event that directly boosts your weekly score.

The model was backtested across multiple recent MLB seasons. The clearest way to communicate what the model does is through quartile calibration:

The 18.4 percentage-point net signal — top quartile vs. bottom quartile — is stronger than what FanGraphs' 2015 WHIP + PPI regression model reported (adjusted R² = 0.427), and our model outputs a per-start probability rather than a seasonal total. No current competitor publishes a per-start QS calibration figure for you to verify. We do.

A 3.50 ERA pitcher gets a QS roughly 55-60% of the time. A 4.00 ERA pitcher gets one 45-50% of the time. Those ranges overlap heavily, and they tell you almost nothing about which of those two starters is the better stream tonight. Season ERA is a long-run average that masks enormous game-to-game variance in command, pitch count efficiency, and depth-of-outing. The pitcher who has allowed 2 earned runs or fewer in his last 7 starts is not the same pitcher as the one who posted 3.50 ERA partly through a fortunate BABIP. Recent outings and command trends are more predictive for the next start than the season number on the platform's roster page.

This is the single most common streaming mistake. A fantasy manager checks “is this a good pitcher?” but not “is this a weak-contact, high-strikeout opponent?” A below-average starter facing a high-K lineup (lots of swing-and-miss, weak grounders when they do make contact) has a materially better QS floor than an above-average pitcher facing a low-K, high-contact lineup that runs up pitch counts through walks, singles, and long at-bats.

The data supports this: teams in the bottom third of league strikeout rate generate the most pitch-count events per inning — forcing starters into 20+ pitch innings, cutting starts short at 80–90 pitches, and turning what should be 6-inning outings into 5.1-inning ones. Our model explicitly encodes opponent K-rate and wOBA in the matchup score — a feature that distinguishes it from every existing streaming tool that evaluates pitchers in isolation.

Coors Field inflates earned runs by 15-20%. A pitcher projecting to allow 3 ER in a neutral-park start may realistically allow 3.5 to 4 at Coors — tipping a borderline 55% P(QS) down to 30-35%. Razzball's matchup score formula uses park factor explicitly, but the average fantasy player does not. Our model includes park-factor adjustment natively, using the same park factors from our deployed Totals V3 model, applied every night based on tonight's starting location.

Some pitchers with perfectly acceptable season ERAs are systematically pulled before the 6-inning threshold by cautious managers. In the modern opener era, bullpen management philosophy affects innings depth independent of run prevention. A pitcher who consistently reaches 5.1 innings while posting a 3.80 ERA may never reach 6 innings because of pitch count protocols — and that means he generates zero QS regardless of how well he pitches.

The model addresses this directly through the IP depth trend feature. A pitcher's average innings per start and the percentage of recent starts reaching 6+ innings both inform his QS probability — so a low-ERA, low-IP pitcher is correctly penalized even when his run prevention looks good. Check the /pitcher-strikeouts page for cross-reference on pitch efficiency.

Two dominant starts in a row make a pitcher “hot” in community discussions. r/fantasybaseball posts, Pitcher List rankings, and FantasyPros streaming articles all respond to recent results in ways that overweight the signal. But a two-start streak in ERA and QS has almost no predictive power for the third start on its own — the correct signal is underlying command metrics (walk rate, first-pitch strike rate, swinging-strike rate) over 10 or more starts, not the last two.

Bayesian shrinkage in the model explicitly corrects for recency bias. A pitcher who has posted 2-for-2 QS over his last two starts does not jump from a 38% baseline to 70% — the model weights the 10-start rolling average and applies shrinkage toward the league mean. This prevents the model from chasing streaks that will revert.

This is the single most expensive mistake on the waiver wire. Any two-start pitcher is not automatically worth streaming. A pitcher with two starts against strong lineups in hitter-friendly parks with poor command metrics is a negative-expected-value stream — and the ERA and WHIP damage from two bad starts can cost you the ratio categories for the entire week.

The correct framework is to evaluate each start independently. Two starts with P(QS) of 0.30 and 0.35 = expected 0.65 QS over the week — worse than one start from a 70%+ confidence arm. Our model makes this expected-value math explicit, and the next section explains exactly how to use it for two-start week decisions.

The standard fantasy baseball week runs Tuesday through Monday on ESPN, CBS, Yahoo, and Fantrax. A two-start week occurs when a pitcher's rotation slot falls on both ends of the 7-day window — typically once every 5 weeks per pitcher, more frequently for teams playing compressed schedules (doubleheaders, rainout makeups).

No current fantasy tool publishes this calculation — but the math is simple and materially changes streaming decisions:

The practical implication: identify the available two-start arms using the community articles (Razzball, FantasyPros), then pull their per-start P(QS) from our model to compute the expected-QS total. An arm with a combined expected QS above 1.0 is a strong stream. An arm below 0.70 is likely worse than a single confirmed 70%+ arm you already have rostered.

Many leagues impose a weekly or seasonal innings cap (1,250–1,500 IP/season is common). As managers approach their limit in August and September, two-start streamers become liabilities rather than assets — adding innings to your cap without necessarily being better than pitchers you already hold. If you are within 50 innings of your limit by the final four weeks of the season, prioritize single-start high-confidence arms over two-start streamers unless you need QS volume for a playoff push.

Before opening the QS page, check this week's two-start pitcher list from Razzball or FantasyPros (published Saturday–Sunday). These are your primary streaming targets. Cross-reference each two-start arm on the QS page and note their per-start P(QS) for each of their two appearances this week. Compute expected QS = P(start 1) + P(start 2). If the combined expected QS is above 0.85, the arm is worth a roster spot in most 6x6 leagues. Below 0.70, evaluate whether you have a better single-start option already on your roster.

Do not stream pitchers with P(QS) below 40%. At 40%, you are getting a QS in only 2 of every 5 starts — below league average — while still running the ERA and WHIP risk of a bad outing in the other 3. In leagues where QS is a category differential (wins minus non-QS starts), a 40% arm is actually a category liability: 60% of his starts actively hurt your ERA/WHIP, and only 40% count as positive QS contributions.

The 40% floor is a rough guide for 6x6 leagues. For CBS/Fantrax points leagues, the relevant threshold is whether the expected fantasy points from the start exceed what a benched pitcher or alternative would produce — which depends on your league's specific scoring weights.

For points leagues where K production matters alongside QS, check our /pitcher-strikeouts page alongside the QS page. A pitcher with 65% P(QS) who is also projected for 8+ strikeouts is a premium stream in any format. The combination of deep innings and high K output is a multiplier in points leagues — it captures the IP points, the K bonus, and the QS bonus if available. A high-K, low-IP pitcher (common in the modern game) hits the K column but misses the QS threshold — useful in 5x5 K leagues, but not in 6x6 QS leagues.

The /games page shows our team-level win probability and total projections for each game. A pitcher whose team is a heavy favorite (70%+ win probability) has a higher chance of his start going long — favored teams rarely pull starters early in blowouts they are winning, and the game script favors deeper outings. Pair high P(QS) with favorable team context for the highest-conviction starts.