The new lineman won't be expected to compete for a starting job, but rather provide backup help for Folau.
As it stands right now, the Dolphins have virtually no one behind Folau and right tackle Todd Wade.
Rookie Brandon Winey is on the practice squad, but the sixth-round pick from LSU is considered a long way from being ready to play in the NFL. Another option is rookie Shawn Draper, who is on the active roster but has played tight end ever since being drafted in the sixth round.
Draper probably is closer to being ready to play tackle in the NFL, but he also probably isn't close to being ready.
So the Dolphins need to protect themselves in case something happens to Folau.
As for Folau, the Dolphins are confident in the former Ravens backup.
"I feel good about Spencer, " said Coach Dave Wannstedt. "We'll be fine there.
"Folau is probably not the athlete that Marcus is from a pass-protection standpoint, but he's every bit as good a player as a run blocker."