The Mariners and Cardinals swapped relievers today, the latter sending RHP Sam Tuivailala to Seattle for prospect Seth Elledge. The deal gives Seattle a marginal bullpen upgrade in Tuivailala (probably over Casey Lawrence) for a stretch run that’s going to require them to continue winning close games. Every slightly better bullpen option is more meaningful in this situation than it is when looking at reliever value from a broader point of view. The deal is also a good fit for St. Louis, who acquires a comparable talent whose service-time calendar better aligns with their competitive schedule. Tuivailala is arbitration-eligible starting in 2020, when Elledge will probably be in his first or second year of big-league service.

Tuivailala is a fine middle reliever. He sits 93-96, will occasionally touch 99, and has two very average secondary offerings in an upper-80s cutter/slider and an upper-70s curveball. The Mariners have had success drafting low-ceiling, high-probability college relievers in the middle rounds of the last several drafts and quickly flipping them for mature big-league pieces on the margins. Elledge was the second pitcher Seattle traded from their 2017 draft class (JP Sears was sent to the Yankees for Nick Rumbelow last fall), which means Seattle’s 2017 draft has technically yielded the most subustantial big-league return in all of baseball right now.

Seth Elledge is a big-bodied, crossfire reliever with a mid-90s fastball and plus breaking ball. He was a 2017 fourth-round pick out of Dallas Baptist, a college that parades hard-throwing relievers into pro ball annually. He has a 54:14 strikeout-to-walk ratio in 38.1 innings. He might eventually be better than Tuivailala because the breaking ball is better. It’s reasonable to project a 2020 debut for Elledge, though has a non-zero chance to debut next year.