The Boston Red Sox, the Houston Astros and the Milwaukee Brewers were tied for allowing the most grand slams in September 2025, with 2 grand slams.
| TEAM | GRANDSLAM | MONTH | G | W% | W | L | GS | ERA | SO | CG | SHO | SV | IP | H | ER | R | HR | BB | HBP | GF | IBB | TBF | WP | K/9 | BB/9 | K/BB | HR/9 | K% | BB% | WHIP | BABIP | RA | H/9 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | Red Sox | 2 | September 2025 | 111 | .561 | 216 | 169 | 25 | 3.78 | 226 | 0 | 0 | 7 | 221.1 | 205 | 93 | 101 | 26 | 74 | 6 | 25 | 1 | 932 | 13 | 9.19 | 3.01 | 3.05 | 1.06 | 24.2 | 7.9 | 1.26 | .298 | 4.11 | 8.34 |
| 2 |  | Astros | 2 | September 2025 | 109 | .475 | 183 | 202 | 25 | 4.07 | 208 | 0 | 0 | 5 | 221.1 | 199 | 100 | 108 | 36 | 77 | 2 | 25 | 0 | 927 | 3 | 8.46 | 3.13 | 2.70 | 1.46 | 22.4 | 8.3 | 1.25 | .270 | 4.39 | 8.09 |
| 3 |  | Brewers | 2 | September 2025 | 108 | .480 | 180 | 195 | 24 | 3.50 | 228 | 0 | 0 | 6 | 213.1 | 177 | 83 | 94 | 22 | 80 | 14 | 24 | 3 | 892 | 4 | 9.62 | 3.38 | 2.85 | 0.93 | 25.6 | 9.0 | 1.20 | .283 | 3.97 | 7.47 |
| 4 |  | Dodgers | 1 | September 2025 | 125 | .612 | 243 | 154 | 26 | 3.32 | 295 | 0 | 0 | 9 | 233.1 | 153 | 86 | 89 | 16 | 106 | 8 | 26 | 10 | 954 | 14 | 11.38 | 4.09 | 2.78 | 0.62 | 30.9 | 11.1 | 1.11 | .259 | 3.43 | 5.90 |
| 5 |  | Reds | 1 | September 2025 | 112 | .515 | 201 | 189 | 26 | 4.18 | 234 | 1 | 1 | 9 | 230.1 | 202 | 107 | 113 | 40 | 71 | 15 | 25 | 2 | 962 | 6 | 9.14 | 2.77 | 3.30 | 1.56 | 24.3 | 7.4 | 1.19 | .269 | 4.42 | 7.89 |
| 6 |  | Cardinals | 1 | September 2025 | 103 | .398 | 140 | 212 | 24 | 4.39 | 187 | 0 | 0 | 7 | 213.1 | 226 | 104 | 118 | 28 | 74 | 8 | 24 | 6 | 930 | 7 | 7.89 | 3.12 | 2.53 | 1.18 | 20.1 | 8.0 | 1.41 | .313 | 4.98 | 9.53 |
| 7 |  | Tigers | 1 | September 2025 | 114 | .289 | 115 | 283 | 25 | 4.63 | 217 | 0 | 0 | 5 | 221.2 | 214 | 114 | 121 | 32 | 88 | 7 | 25 | 1 | 954 | 8 | 8.81 | 3.57 | 2.47 | 1.30 | 22.7 | 9.2 | 1.36 | .298 | 4.91 | 8.69 |
| 8 |  | Orioles | 1 | September 2025 | 112 | .576 | 213 | 157 | 25 | 3.90 | 226 | 0 | 0 | 7 | 223.2 | 200 | 97 | 105 | 30 | 84 | 6 | 25 | 5 | 931 | 13 | 9.09 | 3.38 | 2.69 | 1.21 | 24.3 | 9.0 | 1.27 | .291 | 4.23 | 8.05 |
| 9 |  | Mets | 1 | September 2025 | 119 | .401 | 157 | 235 | 25 | 4.95 | 211 | 0 | 0 | 4 | 218.0 | 221 | 120 | 129 | 27 | 74 | 14 | 25 | 0 | 939 | 12 | 8.71 | 3.06 | 2.85 | 1.11 | 22.5 | 7.9 | 1.35 | .316 | 5.33 | 9.12 |
| 10 |  | Mariners | 1 | September 2025 | 116 | .684 | 266 | 123 | 25 | 3.37 | 256 | 0 | 0 | 7 | 227.0 | 194 | 85 | 92 | 26 | 45 | 12 | 25 | 2 | 919 | 7 | 10.15 | 1.78 | 5.69 | 1.03 | 27.9 | 4.9 | 1.05 | .290 | 3.65 | 7.69 |
| 11 |  | Rockies | 1 | September 2025 | 101 | .156 | 55 | 298 | 25 | 6.00 | 181 | 0 | 0 | 4 | 213.0 | 236 | 142 | 152 | 49 | 76 | 20 | 25 | 2 | 951 | 5 | 7.65 | 3.21 | 2.38 | 2.07 | 19.0 | 8.0 | 1.46 | .299 | 6.42 | 9.97 |
| 12 |  | Diamondbacks | 1 | September 2025 | 108 | .484 | 180 | 192 | 24 | 4.53 | 188 | 0 | 0 | 4 | 216.1 | 201 | 109 | 122 | 31 | 69 | 5 | 24 | 1 | 916 | 4 | 7.82 | 2.87 | 2.72 | 1.29 | 20.5 | 7.5 | 1.25 | .273 | 5.08 | 8.36 |
| 13 |  | Rays | 1 | September 2025 | 116 | .380 | 149 | 243 | 26 | 4.20 | 237 | 0 | 0 | 4 | 227.0 | 203 | 106 | 119 | 28 | 85 | 13 | 26 | 1 | 963 | 10 | 9.40 | 3.37 | 2.79 | 1.11 | 24.6 | 8.8 | 1.27 | .292 | 4.72 | 8.05 |
StatMuse has game-level data for grand slams allowed going back to the 1920 season.
Some of the information used here was obtained free of charge from Retrosheet.
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