The Chicago White Sox host the Seattle Mariners on May 21, 2025. First pitch from Rate Field is scheduled for 2:10 p.m. EDT; the game will be broadcast on ROOT Sports NW.
Read our Mariners vs White Sox prediction and MLB picks below.
My Mariners vs White Sox Prediction
- Mariners vs White Sox Picks: Under 8 (+100, BetMGM)
My Mariners vs White Sox best bet is on the Under. Check our live MLB odds page to find the best odds.
Mariners vs White Sox Odds
| Mariners Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
-1.5 +115 | 8 -120o / -100u | -150 |
| White Sox Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
+1.5 -140 | 8 -120o / -100u | +125 |
Mariners vs White Sox Projected Starting Pitchers
| RHP Logan Evans (SEA) | Stat | RHP Shane Smith (CHW) |
|---|---|---|
| 2-1 | W-L | 1-3 |
| 0.2 | fWAR (FanGraphs) | 1.2 |
| 2.57 / 4.68 | ERA / xERA | 2.05 / 3.44 |
| 4.14 / 4.69 | FIP / xFIP | 3.15 / 4.05 |
| 1.52 | WHIP | 1.14 |
| 6.5% | K-BB% | 13.4% |
| 37.1% | GB% | 43.8% |
| 99 | Stuff+ | 95 |
| 98 | Location+ | 105 |
Tanner McGrath’s Mariners vs White Sox Preview
A wild Bet Labs system popped up for this game.
Since 2018, Unders are 464-346-32 in MLB regular-season games after the same two teams combined for two or fewer runs in the prior game. They hit at a 57% clip and have generated a 10.5% ROI.
The thought is that these matchups tend to reflect stronger-than-expected pitching or cold offenses, and the market doesn’t adjust the total for the next game downward enough. And if you filter for more recent seasons to reflect current scoring environments and pitcher usage trends, the system is even more profitable.
So, after the White Sox beat the Mariners 1-0 on Tuesday, I’ll be heading back and betting the Under between the two on Wednesday.
I have no problem betting the Under on a White Sox game. They’re the third-worst MLB offense by wRC+ (75), and the bats have gone ice-cold recently, slashing .212/.256/.339 for a 66 wRC+ over the past two weeks.
The Mariners are surprisingly batting above their heads on the year (114 wRC+), but they’ve cooled off over the past fortnight (83 wRC+).
Plus, I really like this pitching matchup.
25-year-old White Sox rookie starting pitcher Shane Smith might be the next Southside breakout candidate. He’s posted a ridiculous 2.05 ERA through his first nine starts. While the underlying metrics indicate regression, he still projects as a decent rotation arm (3.44 xERA, 3.15 FIP, 4.05 xFIP, 13.4% strikeout minus walk rate, 105 Pitching+).
Much of the same could be said for 23-year-old Mariners rookie starting pitcher Logan Evans, who has posted a 2.57 ERA through his first 21 MLB innings. He’s due for much more regression than Smith (4.68 xERA, 4.14 FIP, 4.69 xFIP), but the White Sox aren’t the lineup to challenge any half-decent young arm.
The Mariners boast an elite bullpen behind closer Andres Munoz, which will help keep the Sox off the scoreboard. I’m worried about the White Sox's lousy, slightly extended bullpen (they used their four highest-leverage relievers on Tuesday), but not enough to talk me off the Under.
It’s also worth mentioning that Rate Field has been a tougher-than-usual place to hit at this year (96 Park Factor, 22nd among MLB ballparks), which can only help our cause.
Pick: Under 8 (+100, BetMGM)
