SEATTLE (AP) — The Seattle Mariners kept up their bullpen overhaul by agreeing to an $800,000, one-year contract with right-handed reliever Keynan Middleton.   Middleton can earn an additional $50,000 in performance bonuses for games: $12,500 each for 30, 40, 50 and 60. The 27-year-old appeared in 13 games last season with the Los Angeles Angels as he worked his way back from Tommy John surgery during 2018. Middleton has appeared in just 24 major league games over the past two seasons. He went 0-1 with a 5.25 ERA last season.