Not sure which game you brehs are watching. Tanaka is dealing. 6 innings, 1 hit, 1 walk, and plenty of weak contact by Houston batters so far. You can probably count the numbers of balls that Houston has hit so far that made it to the OF on one hand, including the one hit.
He and Sanchez are on a roll and executing the strategy perfectly. He's sonning the Astros and pitching a 1 hitter. Leave him out there for 9 innings. He's only thrown 68 pitches though 6 innings. They obviously haven't and won't figure him out. Until we see any solid contact, don't tamper with success. No panic bullpen moves where not needed.