Castillo will likely be tabbed as the opener for Wednesday's "bullpen day" game, Marc Topkin of the Tampa Bay Times reports.

EDGE Analysis

The right-hander has been stellar in August, generating a 1.38 ERA on the strength of eight scoreless efforts over nine appearances. Castillo has been utilized as both traditional reliever and "bullpen day" opener, and his workload has yet to exceed 2.2 innings in any one outing. The 24-year-old owns a solid 3.23 ERA and 1.05 WHIP across 39.0 innings this season, along with a 41:16 K:BB.