HOUSTON (AP) — As it turns out, the curious decision to trade star receiver DeAndre Hopkins in the offseason was the beginning of the end for Houston Texans coach and general manager Bill O’Brien. Running back David Johnson, acquired from Arizona along with draft picks in exchange for Hopkins, has struggled for the Texans, who are off to their first 0-4 start since 2008. Houston’s run defense has regressed, too. Owner Cal McNair decided Monday he had seen enough from O’Brien and fired him. O’Brien was in his seventh season as coach and assumed the duties of general manager in the offseason.