Castillo is scheduled to start Tuesday against the Cardinals, Mark Zuckerman of MASN Sports reports.
Castillo was originally expected to get the ball for Sunday's series finale against the Nationals, but Sonny Gray will make that start instead. The young right-hander should benefit from some extra rest before his next outing; over his last two starts, Castillo has allowed seven runs (six earned) on 11 hits with a 6:7 K:BB in eight innings.