Mets vs Rays Prediction, August 31, 2026 | Rays moneyline
Robert Stock vs Ian Seymour at Tropicana Field
Published August 31, 2026 · MLB Prediction Data Lab
The moneyline on Rays at -168 is a run-prevention bet first. Robert Stock projects 5.60 earned runs allowed across a 4.13-inning start plus relief; Ian Seymour projects 4.55. The side that prevents more does not have to outslug anyone.
Full slate: MLB picks today, August 31, 2026.
The listed matchup
New York Mets (61–76) at Tampa Bay Rays (82–54), Tropicana Field, St. Petersburg. Robert Stock, a right-hander, is listed for the visitors. Ian Seymour, a left-hander, is listed for the home club. Void the play if either listed starter is scratched.
| Side | Listed starter | Record | Park |
|---|---|---|---|
| Mets | Robert Stock | 61–76 | Tropicana Field |
| Rays | Ian Seymour | 82–54 | Dome, artificial turf |
The two starters, measured per batter faced
Rate statistics expressed per nine innings reward pitchers who work deep. Expressing them as a share of batters faced removes that distortion. Robert Stock has faced 104 hitters. Ian Seymour has faced 446.
| Starter | BF | K% | BB% | K−BB | K/BB | Pitches/BF |
|---|---|---|---|---|---|---|
| Robert Stock | 104 | 20.2 | 12.5 | 7.7 | 1.62 | 3.88 |
| Ian Seymour | 446 | 28.7 | 7.2 | 21.5 | 4.00 | 3.89 |
| Starter | W-L | ERA | IP | WHIP | K/9 | BB/9 | HR/9 | Opp AVG |
|---|---|---|---|---|---|---|---|---|
| Robert Stock (R) | —-3 | 7.40 | 20.2 | 1.94 | 9.15 | 5.66 | 0.87 | .307 |
| Ian Seymour (L) | 9-5 | 4.21 | 107.0 | 1.15 | 10.77 | 2.69 | 1.60 | .225 |
Robert Stock sits at a 7.40 ERA with a 1.94 WHIP and 13 walks in 20.2 innings. Ian Seymour sits at a 4.21 ERA with a 1.15 WHIP and 32 walks in 107.0 innings. Walks stabilize faster than earned runs, so the walk column is the more trustworthy August reading.
Direction inside the season
Season aggregates hide the last month. These are the prior starts, excluding today's outing so the table does not leak a result into a published prediction.
| Robert Stock — last starts | IP | ER | K | BB | H | HR | Pitches |
|---|---|---|---|---|---|---|---|
| 2026-08-02 | 5.0 | 1 | 4 | — | 3 | 1 | 70 |
| 2026-08-08 | 3.0 | 8 | 4 | 5 | 9 | — | 80 |
| 2026-08-14 | 4.1 | 0 | 5 | 3 | 3 | — | 84 |
| 2026-08-19 | 4.1 | 1 | 6 | 3 | 2 | — | 83 |
| 2026-08-26 | 4.0 | 7 | 2 | 2 | 10 | 1 | 87 |
| Ian Seymour — last starts | IP | ER | K | BB | H | HR | Pitches |
|---|---|---|---|---|---|---|---|
| 2026-08-03 | 6.0 | 2 | 9 | — | 7 | 1 | 90 |
| 2026-08-09 | 6.0 | 1 | 7 | 2 | 5 | — | 98 |
| 2026-08-15 | 6.0 | 3 | 9 | 1 | 6 | 2 | 93 |
| 2026-08-20 | 5.0 | 3 | 8 | 1 | 6 | 3 | 90 |
| 2026-08-25 | 5.2 | 3 | 5 | — | 7 | 1 | 88 |
The run environment, before the starters
Mets have scored 562 runs in 137 games (4.10 per game) with a .695 OPS. Rays have scored 616 in 136 (4.53) with a .733 OPS. The pitching staffs have allowed 4.49 and 4.13 runs per game.
| Club | Record | R/G | OPS | Staff ERA | Staff WHIP | RA/G |
|---|---|---|---|---|---|---|
| Mets | 61–76 | 4.10 | .695 | 4.08 | 1.30 | 4.49 |
| Rays | 82–54 | 4.53 | .733 | 3.77 | 1.15 | 4.13 |
Reassembling the buckets
Robert Stock averages 4.13 innings per start. Ian Seymour averages 9.73. Weight each starter's own earned run average across that length, then hand the remainder of the nine innings to his club's season staff rate. That is a conservative relief proxy — it mixes rotation and bullpen — and it is stated as a limitation, not hidden.
| Side | Starter IP | Starter ERA | Relief IP | Staff ERA | Projected ER |
|---|---|---|---|---|---|
| Mets (Robert Stock) | 4.13 | 7.40 | 4.87 | 4.08 | 5.60 |
| Rays (Ian Seymour) | 9.73 | 4.21 | 0.00 | 3.77 | 4.55 |
| Combined | 10.15 |
A combined 10.15 projected earned runs. Unearned runs are ignored. Neither starter hits his average length every night. The opposing lineups are not in the formula; they sit in the table above.
The park
Tropicana Field is listed at 315 feet to left, 410 feet to left center, 404 feet to center, 404 feet to right center, 322 feet to right, on artificial turf, dome at 15 feet above sea level with a listed capacity of 25,025. Park dimensions do not decide a total by themselves. They decide whether a walk plus a ball in the air becomes two runs or a long out.
Where this reading is weakest
Moneyline edges this thin die when the length assumption fails. If the better starter is out in the fourth, the staff rate takes over and the partition no longer applies.
What would falsify it
A short outing from the starter on the backed side, or a crooked inning against the relief bucket that the partition treats as average, is the miss. The model is only as good as the length assumption of 4.13 and 9.73 innings.
The position
Tampa Bay Rays Moneyline at -168, 1.5 units. A price of -168 implies a 62.7% break-even. Grade it against this published number. If a listed starter is scratched, the play is void.
- Tampa Bay Rays Moneyline -168 · 1.5u
Who is on the mound?
Robert Stock for Mets. Ian Seymour for Rays. Those names come from the MLB probable-pitcher feed, not from a guessed rotation.
Why use batters-faced rates instead of ERA?
Earned run average is a counting result. Strikeout and walk rates as a share of batters faced describe the process that produced it, and they stabilize on a smaller sample. Robert Stock at 7.7 points of K−BB separation versus Ian Seymour at 21.5 is the comparison ERA hides.
How is the pick graded?
Against the published price, on the public record. Pending is not a win. Today's full card lives at a stable URL: mlb-picks.html.
Pick, odds, and unit size come from the BetLegend daily tracker. Probable starters, season rates, and venue facts are from the MLB Stats API. Educational analysis. 18+ only. 1-800-GAMBLER.