Martinez and Soto join right-handed relievers Gavin Floyd and Shawn Armstrong and corner infielder Chris Johnson as the five players the Indians have added since rosters expanded on Tuesday.
Soto is a 24-year-old former starting pitcher who has turned heads with impressive performances since transitioning to the bullpen. At Double-A Akron last season -- his first as a full-time reliever -- Soto carried a 3.23 ERA and a 2.73 Fielding Independent Pitching in 53 relief innings. This year, in Triple-A Columbus, he has a 2.