The Houston Astros host the Seattle Mariners on May 22, 2025. First pitch from Daikin Park is scheduled for 8:10 p.m. ET; the game will be broadcast on SCHN.
AL West leaders Seattle and Houston will begin an important four-game series on Thursday, with the Mariners currently holding a 3.5-game lead in the division. George Kirby will make his first start of the season versus Lance McCullers Jr., who will be making only his third appearance of the year.
Find my MLB betting preview and Mariners vs Astros prediction below, as well as probable pitchers, betting trends, injury reports and more.
My Mariners vs Astros Prediction
- Mariners vs Astros pick: Mariners F5 -135 (bet365, Play to -140)
My Mariners vs Astros best bet is the Mariners F5 moneyline. Make sure to find the best odds by checking our live MLB odds page.
Mariners vs Astros Odds
| Mariners Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
-1.5 +125 | 8.5 -110o / -110u | -135 |
| Astros Odds | ||
|---|---|---|
| Spread | Total | Moneyline |
+1.5 -155 | 8.5 -110o / -110u | +115 |
Mariners vs Astros Projected Starting Pitchers
| RHP George Kirby (SEA) | Stat | RHP Lance McCullers Jr. (HOU) |
|---|---|---|
| 0-0 (season debut) | W-L | 0-1 |
| — | fWAR (FanGraphs) | -0.1 |
| — | ERA /xERA | 7.88/8.74 |
| — | FIP / xFIP | 6.95/6.78 |
| — | WHIP | 2.13 |
| — | K-BB% | -2.2% |
| — | GB% | 44.8 |
| — | Stuff+ | 94 |
| — | Location+ | 85 |
Nick Martin’s Mariners vs Astros Preview
Seattle Mariners Betting Preview: All Eyes on Kirby's Season Debut
The Mariners have to be feeling pretty good about where they stand after the first 48 games of the season. That's especially true given that Kirby has yet to make an appearance and All-Star Logan Gilbert has pitched only 30 1/3 innings. Gilbert is nearing a return to action.
Kirby has pitched to an ERA of 3.43 across his first 511 2/3 innings of work in the MLB, including an ERA of 3.53 last season. He's been on the injured list since March 24 with inflammation in his throwing shoulder and will likely be eased back into action fairly cautiously.
Kirby threw 64 pitches in his third rehab start on Friday and offered his typical level of velocity, as his fastball topped out at 98. He did allow four earned runs, but as is the case with all spring training outings for experienced starters, that likely won't be overly indicative of how he'll perform in a meaningful setting.
In 191 innings last season, Kirby finished with a 3.44 xERA and 3.58 xFIP. He held a Stuff+ rating of 104 and a Pitching+ rating of 112.
The Mariners haven't been as reliant on their starters to post elite results in order to find success this season, as they currently rank sixth in offensive wRC+ and hold an OPS of .723.
It may not be a trend that continues all season long, but they've been much more effective on the road offensively, with a wRC+ of 120.
Seattle has also been effective versus right-handed pitching, as it holds a wRC+ of 113 and ranks fourth in BB/K ratio.
Houston Astros Betting Preview: McCullers Searches for Form
Houston's pitching staff currently holds the seventh-best ERA in MLB, which has helped the team scrape together an above .500 record despite a slow start to the season.
The Astros' bullpen currently holds the second-best ERA in baseball, but aside from Hunter Brown and Framber Valdez, the starting staff hasn't been overly effective and the team will receive a huge boost if McCullers is able to return to top form.
McCullers missed the 2023 and 2024 seasons after undergoing elbow surgery to repair a flexor tendon tear. In his first eight innings of work since returning to the Astros, he's pitched to an 8.74 xERA and 6.78 xFIP and has a Pitching+ rating of 84.
Those numbers were marred by a horrific outing on May 10 versus the Cincinnati Reds in which he allowed seven earned runs while recording only one out. He was able to bounce back with four scoreless innings in his last outing versus the Rangers.
The most proven bats in the Astros' lineup have all had horrible starts to the season, as Jose Altuve, Christian Walker and Yordan Alvarez all currently hold wRC+ ratings below 80. Alvarez is currently sidelined with a muscle strain on his right hand, but he's nearing a return to the lineup.
Despite a lack of production from their top stars, the Astros have managed to hit to a wRC+ rating of 100 versus right-handed pitching and rank 11th in hard-hit rate.
Mariners vs Astros Prediction, Betting Analysis
While McCullers' overall statistics are currently heavily inflated by one shocking outing, it still seems reasonable to believe that he may offer below-average results this season based upon his quality of stuff through his initial three outings.
With this being Kirby's first start of the season, it offers a higher level of volatility. However, the higher range of outcomes does seem to be baked into the betting numbers on this game.
If he had a few quality outings under his belt, the Mariners would likely be much larger favorites in this matchup, given the edge he's expected to offer compared to McCullers.
That's especially true considering that the Mariners have been the more productive team offensively, particularly in the splits most relevant to this matchup.
At -135, there's value backing the Mariners to win the first five innings as one of the better starters in the AL makes his season debut.
Pick: Mariners F5 Moneyline -135 (bet365, Play to -140)
Moneyline
Obviously my lean in terms of betting the moneyline would be backing the Mariners at -135, but there looks to be more value isolating the Kirby versus McCullers innings at the same price.
Run Line (Spread)
Backing the Mariners to cover the run line at +115 would be my preferred play, but this is a bet I'll ultimately be passing on.
Over/Under
My lean would be with the under in terms of betting the total, as my thought process in betting the Mariners to win the first five innings revolves mainly around my belief that Kirby will return with a strong outing. Meanwhile, McCullers will be as awful as his current numbers suggest.
