Santiago had his contract selected from Triple-A Syracuse on Monday, Tim Healey of Newsday reports.
Santiago will replace Seth Lugo (shoulder) -- who was placed on the injured list Monday -- on the 25-man roster, while Jed Lowrie (hamstring) was shifted to the 60-day IL to free up a spot on the 40-man. The veteran right-hander has worked primarily as a starter in the minors this season, compiling a 3.35 ERA, 1.28 WHIP and 38:23 K:BB in 43 innings with Syracuse (eight starts, one relief appearance), so he'll likely fill a long-relief role during his time with the big club.