MLB bullpen report — 2026-09-12

Which bullpens are rested tonight, and which ones are running on fumes. Every active reliever on tonight's slate is scored on three things: how much he has thrown in the last three days, how long since he last appeared, and his SIERA — the ERA estimator that describes a pitcher better than his ERA does. Teams are listed with the thinnest bullpen first.

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Two questions this page answers

Short clips, no sound, captions only.

Which bullpen is running on fumes tonight?
Why SIERA instead of ERA?

How a bullpen gets read here

Rested, recent, overworked. A reliever who threw yesterday is not the same arm as one who has had two days off, and a reliever who has thrown on three of the last four days is often unavailable whatever the box score says. Workload is read from pitch counts over the last three days and days since the last appearance.

Depth, not names. A bullpen with one excellent closer and nothing behind him is thinner than it looks the night that closer is down. Each team is scored on its top three arms weighted by availability, plus the rested arms on the bench that are good enough to matter (under 4.00 SIERA).

SIERA rather than ERA. ERA on fifty relief innings is mostly noise — it moves on defence, sequencing and luck. SIERA is built from strikeouts, walks and batted-ball type, which stabilise far faster. Arms without enough innings for a trustworthy SIERA are shown unrated instead of being given a number nobody should trust.

This page shows what the data says. What you do with it is your business — we never publish predictions.

15 games today · all times ET · recomputed every 15 minutes

Colorado Rockies at Detroit Tigers · 1:10 PM ET

Colorado Rockies

Thin bullpen

Top arms: Castaño (3.73, recent), Frasso (3.96, recent), Manfredi (4.06, recent) · 1 rested · 4 recent · 0 overworked · best rested arm: Herget 4.67 SIERA

  • Top arm Castaño (3.73 SIERA) 🟡 recent
  • Thin behind top arms

Detroit Tigers

Thin bullpen

Top arms: Anderson (3.58, rested), Holton (3.66, recent), Jansen (4.06, recent) · 3 rested · 4 recent · 0 overworked · best rested arm: Anderson 3.58 SIERA

Kansas City Royals at Boston Red Sox · 4:10 PM ET

Kansas City Royals

Thin bullpen

Top arms: Cruz (3.39, recent), Lange (4.00, rested), Kimbrel (4.26, rested) · 5 rested · 4 recent · 1 overworked · best rested arm: Lange 4.00 SIERA

  • Top arm Cruz (3.39 SIERA) 🟡 recent
  • Thin behind top arms

Boston Red Sox

Deep bullpen

Top arms: Whitlock (2.55, rested), Chapman (2.93, rested), Miller (3.13, recent) · 6 rested · 3 recent · 0 overworked · best rested arm: Whitlock 2.55 SIERA

  • +3 rested bench arms <4.0 SIERA

Chicago White Sox at St. Louis Cardinals · 7:15 PM ET

Chicago White Sox

Average bullpen

Top arms: Taylor (2.70, rested), Hudson (3.61, rested), Smith (3.84, recent) · 5 rested · 2 recent · 2 overworked · best rested arm: Taylor 2.70 SIERA

St. Louis Cardinals

Thin bullpen

Top arms: Gastelum (2.98, recent), O'Brien (3.71, recent), Stanek (3.96, recent) · 4 rested · 5 recent · 0 overworked · best rested arm: Soriano 4.05 SIERA

  • Top arm Gastelum (2.98 SIERA) 🟡 recent

Los Angeles Angels at Washington Nationals · 4:05 PM ET

Los Angeles Angels

Average bullpen

Top arms: Jr. (2.44, recent), Saucedo (2.79, rested), Joyce (3.03, rested) · 5 rested · 4 recent · 0 overworked · best rested arm: Saucedo 2.79 SIERA

  • Top arm Jr. (2.44 SIERA) 🟡 recent
  • +3 rested bench arms <4.0 SIERA

Washington Nationals

Thin bullpen

Top arms: Dion (3.00, recent), Lord (3.64, recent), Yean (4.10, recent) · 5 rested · 5 recent · 0 overworked · best rested arm: Cruz 4.46 SIERA

  • Top arm Dion (3.00 SIERA) 🟡 recent

Seattle Mariners at Athletics · 9:40 PM ET

Seattle Mariners

Average bullpen

Top arms: Muñoz (2.22, recent), Rucker (3.23, rested), Vargas (3.27, recent) · 4 rested · 5 recent · 0 overworked · best rested arm: Rucker 3.23 SIERA

  • Top arm Muñoz (2.22 SIERA) 🟡 recent
  • +2 rested bench arms <4.0 SIERA

Athletics

Thin bullpen

Top arms: Blewett (3.29, recent), Medina (3.57, recent), Alvarado (3.58, recent) · 4 rested · 5 recent · 1 overworked · best rested arm: Perkins 3.91 SIERA

  • Top arm Blewett (3.29 SIERA) 🟡 recent

Cincinnati Reds at Milwaukee Brewers · 7:10 PM ET

Cincinnati Reds

Thin bullpen

Top arms: Antone (3.37, recent), Mey (3.40, overworked), Garcia (3.73, recent) · 4 rested · 3 recent · 1 overworked · best rested arm: Ashcraft 3.74 SIERA

  • Top arm Antone (3.37 SIERA) 🟡 recent
  • Setup Mey (3.40 SIERA) 🔴 overworked
  • +2 rested bench arms <4.0 SIERA

Milwaukee Brewers

Average bullpen

Top arms: Megill (2.85, rested), Ashby (2.96, rested), Stallings (3.20, recent) · 6 rested · 2 recent · 0 overworked · best rested arm: Megill 2.85 SIERA

  • +2 rested bench arms <4.0 SIERA

New York Mets at New York Yankees · 1:35 PM ET

New York Mets

Average bullpen

Top arms: Lavender (2.64, rested), Núñez (3.00, rested), Duarte (3.14, recent) · 5 rested · 3 recent · 0 overworked · best rested arm: Lavender 2.64 SIERA

New York Yankees

Thin bullpen

Top arms: Headrick (2.78, recent), Bednar (2.89, recent), Blackburn (3.74, recent) · 1 rested · 4 recent · 0 overworked · best rested arm: none

  • Top arm Headrick (2.78 SIERA) 🟡 recent

Baltimore Orioles at Toronto Blue Jays · 3:07 PM ET

Baltimore Orioles

Thin bullpen

Top arms: Cano (2.88, recent), Garcia (3.36, recent), Hoppe (3.50, recent) · 3 rested · 5 recent · 0 overworked · best rested arm: Nunez 3.82 SIERA

  • Top arm Cano (2.88 SIERA) 🟡 recent

Toronto Blue Jays

Average bullpen

Top arms: Varland (2.37, rested), Sewald (3.75, recent), Fluharty (3.78, rested) · 3 rested · 4 recent · 0 overworked · best rested arm: Varland 2.37 SIERA

Pittsburgh Pirates at Chicago Cubs · 2:20 PM ET

Pittsburgh Pirates

Average bullpen

Top arms: Montgomery (2.23, recent), Weaver (3.16, recent), Eisert (3.28, recent) · 2 rested · 7 recent · 1 overworked · best rested arm: Ramírez 3.76 SIERA

  • Top arm Montgomery (2.23 SIERA) 🟡 recent

Chicago Cubs

Thin bullpen

Top arms: Thielbar (3.23, rested), Palencia (3.31, recent), Zeferjahn (3.44, rested) · 2 rested · 2 recent · 0 overworked · best rested arm: Thielbar 3.23 SIERA

Los Angeles Dodgers at Miami Marlins · 4:10 PM ET

Los Angeles Dodgers

Average bullpen

Top arms: Scott (2.48, rested), Dreyer (3.01, rested), Phillips (3.15, recent) · 4 rested · 4 recent · 0 overworked · best rested arm: Scott 2.48 SIERA

Miami Marlins

Thin bullpen

Top arms: Zuber (3.08, recent), Fairbanks (3.20, rested), Petersen (3.46, rested) · 4 rested · 5 recent · 0 overworked · best rested arm: Fairbanks 3.20 SIERA

  • Top arm Zuber (3.08 SIERA) 🟡 recent

Cleveland Guardians at Minnesota Twins · 4:10 PM ET

Cleveland Guardians

Average bullpen

Top arms: Smith (2.46, recent), Sabrowski (3.14, recent), Festa (3.38, recent) · 1 rested · 6 recent · 0 overworked · best rested arm: Yoho 3.68 SIERA

  • Top arm Smith (2.46 SIERA) 🟡 recent

Minnesota Twins

Average bullpen

Top arms: Hoffman (2.59, recent), Nance (3.37, rested), Minter (3.43, recent) · 3 rested · 5 recent · 0 overworked · best rested arm: Nance 3.37 SIERA

  • Top arm Hoffman (2.59 SIERA) 🟡 recent

Philadelphia Phillies at Atlanta Braves · 7:15 PM ET

Philadelphia Phillies

Average bullpen

Top arms: Duran (1.70, recent), Bowlan (2.51, recent), Shugart (3.35, recent) · 1 rested · 6 recent · 0 overworked · best rested arm: Kerkering 4.15 SIERA

  • Top arm Duran (1.70 SIERA) 🟡 recent

Atlanta Braves

Average bullpen

Top arms: Lee (2.64, recent), Fuentes (2.72, recent), Iglesias (3.34, recent) · 4 rested · 4 recent · 1 overworked · best rested arm: Dodd 3.43 SIERA

  • Top arm Lee (2.64 SIERA) 🟡 recent
  • +2 rested bench arms <4.0 SIERA

San Diego Padres at San Francisco Giants · 4:05 PM ET

San Diego Padres

Average bullpen

Top arms: Miller (1.43, recent), Morejon (2.47, recent), Rodriguez (3.12, recent) · 4 rested · 4 recent · 0 overworked · best rested arm: Hart 3.56 SIERA

  • Top arm Miller (1.43 SIERA) 🟡 recent

San Francisco Giants

Average bullpen

Top arms: Harris (2.68, rested), Smith (3.35, rested), Sanmartin (3.45, rested) · 6 rested · 1 recent · 3 overworked · best rested arm: Harris 2.68 SIERA

  • 3 🔴 overworked

Houston Astros at Tampa Bay Rays · 6:10 PM ET

Houston Astros

Average bullpen

Top arms: Hader (2.18, rested), Santos (3.67, rested), Blubaugh (3.77, rested) · 4 rested · 3 recent · 0 overworked · best rested arm: Hader 2.18 SIERA

Tampa Bay Rays

Average bullpen

Top arms: Kelly (2.71, rested), Booser (2.85, rested), Baker (3.28, recent) · 5 rested · 3 recent · 0 overworked · best rested arm: Kelly 2.71 SIERA

Texas Rangers at Arizona Diamondbacks · 8:10 PM ET

Texas Rangers

Average bullpen

Top arms: Williams (2.92, rested), Latz (3.04, rested), Montgomery (3.39, recent) · 5 rested · 5 recent · 0 overworked · best rested arm: Williams 2.92 SIERA

Arizona Diamondbacks

Average bullpen

Top arms: Garcia (2.20, rested), Morillo (3.08, rested), Ginkel (3.39, recent) · 4 rested · 4 recent · 0 overworked · best rested arm: Garcia 2.20 SIERA

The rest of the picture

Bullpens are one screen of it. The full slate adds starting pitchers with their splits by batter side, confirmed lineups as they land, park and wind, and league-wide leaderboards — all in one place, refreshed through the day.

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