Marshall, 27, was claimed off waivers out of the Diamondbacks organization back in early April and appeared in six games for the Mariners this season before landing on the shelf for a significant period of time due to a hamstring injury. In his 7 2/3 frames with Seattle this season, he surrendered eight runs on a dozen hits and five walks with four strikeouts.
It’s now been three years since Marshall enjoyed prolonged success in the Majors. As a 24-year-old rookie back in 2014, he worked 49 1/3 innings out of the Arizona bullpen and averaged a hearty 9.9 K/9 against 3.1 BB/9 with a sensational 60.7 percent ground-ball rate. Since that time, though, Marshall has just 36 1/3 Major League innings to his credit with a 7.93 earned run average. His ground-ball and strikeout rates have each plummeted since that promising rookie showing, and his walk rate has gone in the opposite direction as well.
Marshall, who has a career 4.30 ERA in parts of five Triple-A seasons, will look to get back on track in Triple-A with the hopes of getting another crack in the Majors later this year.