The problem is that these states end as quickly as they begin. A player on a hot streak will only continue to hit until he is no longer hot and that can happen in his next at bat. Tango, et al showed in The Book that being on a hot or cold streak has little predictive value. Players have a strong propensity to hit at their norms regardless of their recent past. Now, if the manager actually sees a real change and thinks it can continue, I guess he can roll with the hot streak. In general though, a hot streak is not indicative of a changed man.
I didn't watch the game today, but I assume he was removed for a lefty? How many of his previous 7 hits were against lefties?