The Washington Nationals tried to upgrade their bullpen, acquiring relievers Roenis Elias and Hunter Strickland from Seattle and Daniel Hudson in a trade with Toronto.
The Mariners received a trio of minor league pitchers from the Nationals - left-handers Taylor Guilbeau and Aaron Fletcher and right-hander Elvis Alvarado.
Elias has been Seattle's primary closer for the majority of the season after Strickland suffered a lat strain in the opening week and missed several months.
Elías, a left-hander who turns 31 on Thursday, went 4-2 with 14 saves and a 4.40 ERA for Seattle.
The 30-year-old Strickland has an 8.10 ERA in four appearances. The right-hander has a 2.98 career ERA over six seasons.
Elías and Strickland are under team control through 2021.
Seattle gets 26-year-old left-hander Taylor Guilbeau, 23-year-old left-hander Aaron Fletcher and 20-year-old right-hander Elvis Alvarado, a former outfielder who converted to pitcher last year.
Guilbeau is ranked as the No. 15 prospect in the Nationals organization by MLB.com. Fletcher is the Nat's No. 21 prospect.
The Mariners then sent starting pitcher Mike Leake to Arizona for minor league infielder Jose Caballero and cash considerations.
The 22-year-old Caballero is batting .268 (44x164) with 36 runs scored, 12 doubles, 3 home runs, 12 RBI, 24 walks and 38 stolen bases in 43 games with High-A Visalia this season. He was named a Mid-Season California League All-Star.
Leake, 31, went 9-8 with a 4.34 ERA (66 ER, 137.0 IP) with 100 strikeouts and 19 walks in 22 starts with the Mariners this season. He's earning $16 million this year, $15M in 2020, and has an $18M option or $5M buyout in 2021.
