2 ways Mariners can guarantee Seranthony Domínguez as a steal in Luis Castillo trade

The Mariners didn't have the most compelling trade deadline this year. The deals they did strike were excellent but the apparent lack of urgency was surprising, especially for a team whose playoff chances hang in the balance. Given Jerry Dipoto's comments from a few weeks ago, the lack of moves should've been expected. But now that the Astros have reclaimed the division, fans were expecting more.

The Mariners added two big names. One is Taylor Ward, a right-handed bat that has excelled against left-handed pitching this year and seems poised to solve one of the lineup's most glaring issues. The other is Seranthony Domínguez, the primary return in a brilliant deal to send Luis Castillo to Chicago. He's a reliever the Mariners faced quite a bit in last year's ALCS and he's been in the big leagues for quite some time.

His numbers have regressed significantly since he joined the White Sox this season, but there's still some upside for Seattle to utilize if they focus on two key areas.

Seranthony Domínguez can help the Mariners by staying in his lane or learning command

1. Use him primarily against right-handed batters

Domínguez has had drastically different results against left-handed and right-handed batters. Lefties have posted a .782 OPS against him, while righties have managed just a .587 across a similar number of plate appearances. His actual results are in line with his expected results, as his xwOBA of .274 against right-handed hitters is far better than the .381 mark he has against left-handed hitters.

Strangely, the reason for this difference doesn't seem to be obvious. Most of his Statcast numbers are similar for batters of both handedness and he actually gives up more contact in the zone and generates fewer ground balls for right-handed hitters. The only arsenal difference is that he throws more sinkers to righties and throws his splitters almost exclusively to lefties.

The platoon advantage for him likely has something to do with the effectiveness of his sweeper, which would break away from righties and towards lefties. Either way, he's clearly shown to be more effective at dealing with one side of the platoon so the Mariners might as well play to his strengths.

2. Improve control of the fastball to set up the secondary pitches

Domínguez has an ERA of 3.99 but a FIP of 4.64 and it's largely due to his 13.9% walk rate. Although he's more than capable of accumulating strikeouts, the free passes have limited his effectiveness and have also led to the occasional grooved pitch when behind in the count.

Part of the reason he found success after being traded to Toronto last year was improved control of his four-seam fastball, which landed in the zone 58.0% of the time. This allowed his secondary pitches to flourish and both his splitter and sweeper boasted whiff rates above 40% while in a Blue Jays uniform.

This year, he's back down to a 51.5% zone rate for his four-seam fastball and although his splitter continues to miss bats, his sweeper and sinker have been less competitive. With slightly less carry on his fastball this year, landing it at the top of the zone should allow the rest of his arsenal to get under bats entirely or at least turn into ground balls.

The White Sox haven't gotten what they've needed out of him this year, but their organization doesn't have a particularly good reputation for turning around pitching reclamation projects. There are arms that are far worse off than Domínguez but as just one of two acquisitions, the Mariners need him to be much more than just another medium leverage bullpen arm. With the right approach, Seranthony can flourish in Seattle and it may be just enough to get the team into the postseason picture.

Add us as a preferred source on Google

Follow