For a Dolphins team that has seen its quarterback room upended by injuries the past three weeks, Wednesday marked a return to normalcy. As the team practiced underneath dreary skies at the Baptist Health Training Complex, they did so knowing that Tua Tagovailoa is back in the lineup. After sustaining a concussion on Sept. 29 and spending the next two weeks in the NFL’s concussion protocol, the third-year player is set to start in Sunday night’s prime-time game against the Pittsburgh Steelers. In the wake of Tagovailoa’s concussion, which placed the NFL’s handling of head injuries back into the…