Seattle’s and Geno Smith’s new center was Tagovailoa’s snapper the previous two seasons. He’s seen him concussed before.

Miami Dolphins quarterback Tua Tagovailoa signed a four-year contract extension. Here's what to know about him, including how to pronounce his name.

None of this matters if Tua is cleared to play. If he’s not cleared, however, the Dolphins will owe every penny of the guaranteed money — possibly if not probably with no insurance money to refund the cash or to secure salary-cap credits.