Seattle Mariners right-hander Casey Legumina will serve as the opener on Tuesday against the hosting Chicago White Sox, according to Seattle Sports' Shannon Drayer. Right-hander Casey Lawrence is on the taxi squad and is expected to be added to the active roster as the bulk reliever for Tuesday's contest. Legumina has been a key reliever for the first-place Mariners this year with a 3-1 record, 1.84 ERA, 1.09 WHIP and 14:8 K:BB in 14 2/3 innings out of the bullpen. This will be the 27-year-old's first actual "start" in the big leagues, but he won't be a recommended DFS streamer, as he'll likely only go an inning or two before handing the ball to Lawrence. The 37-year-old Lawrence should also be avoided for fantasy purposes, even against the struggling White Sox. He's allowed 14 runs (seven earned) while walking one and striking out five in 12 2/3 relief innings for Seattle and Toronto in 2025.

The Seattle Mariners have signed pitchers Sean Poppen and Casey Lawrence to minor-league deals while both players have received an invitation to big-league spring training. Poppen, 29, didn't appear in the big leagues in the 2023 season but rather scuffled to a 6.33 ERA across 47 outings at Triple-A El Paso within the Padres organization. He owns a career 5.08 ERA across 63 MLB appearances between the Twins, Pirates, Rays, and D-backs. Lawrence, 36, appeared in 15 games for the Cardinals last season but scuffled to a 6.59 ERA across 27 1/3 innings of work. He also tossed a 4.76 ERA across 104 innings at the Triple-A level between the Cardinals and Blue Jays organizations. Lawrence owns a career 6.75 ERA across 59 MLB appearances between the Blue Jays, Mariners, and Cardinals.