The Mariners acquired Simpson from the Marlins on Monday in exchange for cash considerations.

EDGE Analysis

Simpson reached the big leagues for the first time in 2025 but was unable to work his way into a high-leverage role with Miami after submitting a 7.34 ERA and 1.83 WHIP in 30.2 innings. The southpaw yielded five home runs over 31 appearances and walked 14.6 percent of the batters he faced, but he generated ground balls at a high rate (59.6 percent) and struck out hitters at a decent clip (23.8 percent). Seattle recognized enough potential in Simpson to bring him aboard as an extra left-handed option out of the bullpen and opened up a 40-man roster spot for him by placing Logan Evans (elbow) on the 60-day injured list.

Simpson was designated for assignment Thursday.

EDGE Analysis

Simpson made his big-league debut in 2025, posting a 7.34 ERA and 1.83 WHIP across 30.2 innings with the Marlins. He walked 22 during that time while also serving up 1.5 HR/9. Those numbers make it little surprise that Simpson lost his roster spot, a move that created room for John King to officially be added to the roster.

The Marlins recalled Simpson from Triple-A Jacksonville on Friday.

EDGE Analysis

Simpson (2-2) has appeared in 23 games out of the Miami bullpen this season and has an ugly 8.87 ERA, 1.79 WHIP and 24:16 K:BB across 22.1 innings of work. He'll likely fill a middle-relief role for the Marlins.

The Marlins optioned Simpson to Triple-A Jacksonville on Wednesday.

EDGE Analysis

One day after being torched for seven runs while retiring just one batter in an 11-2 loss to Atlanta, Simpson finds himself back in the minors. Seth Martinez and Freddy Tarnok were called up from Jacksonville to supplement the Marlins bullpen.

Simpson (2-0) picked up the win Friday over the Brewers, striking out one in a perfect sixth inning.

EDGE Analysis

The 27-year-old southpaw has emerged as a strong option in the Marlins' bullpen since his rough big-league debut June 21 against Atlanta. Over his last 10 appearances and 11 innings, Simpson has posted a 0.82 ERA, 0.91 WHIP and 15:5 K:BB while recording two wins and a hold.

The Marlins selected Simpson's contract from Triple-A Jacksonville on Saturday.

EDGE Analysis

Simpson will join the Marlins' bullpen after logging a 3.41 ERA and 1.03 WHIP across 31.2 innings in Triple-A. He'll likely work in middle relief while in Miami, and he will replace Robinson Pina on both the 26-man and 40-man rosters.

Simpson walked one and struck out five over 2.1 scoreless, no-hit innings in Thursday's Grapefruit League game against the Astros.

EDGE Analysis

The 27-year-old southpaw lost his spot on the 40-man roster during the offseason, but Simpson's performance in camp -- plus the Marlins' lack of established relief options from the left side -- has put him back on the radar. Simpson has a 12:4 K:BB through 9.1 Grapefruit League innings, and he's out-pitched Anthony Veneziano, who has an 8:7 K:BB in 9.2 spring frames. If Simpson does break camp on the 26-man roster, he may work in long relief behind an injury-ravaged rotation.

Simpson cleared waivers and was outrighted off the Marlins' 40-man roster Monday.

EDGE Analysis

A 27-year-old southpaw, Simpson had surgery in April to repair the ulnar nerve in his left elbow and was able to return late in the year with a rehab assignment before being assinged to Triple-A. Simpson logged a 7.62 ERA, 1.77 WHIP and a 19:7 K:BB in his final 13 innings last season and has never reached the big leagues.

The Marlins activated Simpson (elbow) from the 60-day injured list and optioned him to Triple-A Jacksonville on Tuesday.

EDGE Analysis

The left-hander had the elbow issue surface in February and underwent surgery to repair the ulnar nerve in late April, but he's been fully cleared after an eight-appearance rehab assignment. Simpson surrendered six runs with an 11:8 K:BB across 8.2 innings during the rehab stint, so he'll be sent to Triple-A rather than joining Miami's bullpen.

Simpson (elbow) is scheduled to begin a rehab assignment Tuesday with Single-A Jupiter, Christina De Nicola of MLB.com reports.

EDGE Analysis

Simpson had already been rehabbing at the Marlins' facility in Jupiter, Fla., and after throwing two innings of live batting practice last Wednesday, he's been given the green light to make a one-inning rehab appearance Tuesday. The left-hander has been out since late April while recovering from surgery to address left elbow neuritis and will require multiple rehab appearances before being activated from the 60-day injured list.