MIAMI (AP) -- The Miami Marlins traded right-hander David Phelps to the Seattle Mariners for four prospects, including highly regarded outfielder Brayan Hernandez, a person familiar with the deal said Thursday.
The person confirmed the trade to The Associated Press on condition of anonymity because the teams hadn't announced it.
Phelps is 2-4 with a 3.45 ERA in 44 games and 47 innings this season, all out of the bullpen. He's a six-year veteran with 64 career starts.
Hernandez, a 19-year-old Venezuelan, is batting .259 in 31 games in the minors this year.
The Mariners made the deal at the start of a key 10-game homestand that starts against the New York Yankees and leads into the trade deadline. After a 5-1 trip following the All-Star break, the Mariners are 48-48 and 1 games behind the Yankees in the AL wild-card standings.
The Marlins are out of playoff contention and looking to upgrade a farm system widely ranked among the worst in the majors.
Phelps will join a Mariners bullpen that's was overworked during the first-half of the season as they dealt with major injuries to the rotation. The Mariners are fifth in the American League in most innings pitched by the bullpen.
Seattle has solidified its eighth- and ninth-inning roles with Nick Vincent typically the setup man for closer Edwin Diaz, but getting to that point has been a struggle at times. Phelps should provide Seattle manager Scott Servais more options to bridge those late innings.
Phelps also fits a desire by general manager Jerry Dipoto to acquire players who aren't short-term rentals. Phelps will be under Seattle's control through the 2018 season.