Spence was penalized in the second quarter for unnecessary roughness on the play. The penalty wiped out a drive-ending sack by Cameron Wake and left the Dolphins with only a couple of defensive linemen.
The ejection was enforced as part of a revision in the NFL's rules that grants referees discretion to disqualify players for egregious infractions, including post-play penalties.
Other such ejections to this point of the season include Cincinnati Bengals defensive back Shawn Williams following his helmet-to-helmet tackle of Indianapolis quarterback Andrew Luck in Week 1 and Atlanta Falcons safety Damontae Kazee's helmet-to-helmet shot on Carolina Panthers quarterback Cam Newton in Week 2.
The loss of Spence opens playing time for second-year defensive tackle Vincent Taylor.
Another Dolphins defensive lineman, William Hayes, left the game with a knee injury earlier in the first half. He became questionable to return to the game.
Hayes sustained the injury during a sack of Raiders quarterback Derek Carr. Hayes was writhing on the ground in pain and his knee was checked by trainers. Hayes was able to walk off the field with some discomfort.
The Dolphins are also playing without starting safety Reshad Jones, who is out with a shoulder injury.