Rookie Raekwon McMillan injures knee in Dolphins' preseason opener

There weren't many highlights from Miami Dolphins starters in their preseason 23-20 win over the visiting Atlanta Falcons, but there was one major lowlight: Rookie linebacker Raekwon McMillan, who was listed as the team's starting middle linebacker entering Thursday night, left the game less than three minutes into the first quarter after injuring his knee in punt coverage. He did not return, and his status is in question.

QB depth chart: There's certainly no quarterback controversy brewing in Miami. Matt Moore got only three snaps, completing his one attempt for 5 yards, before coach Adam Gase took out the first-team offense after a three-and-out. QB Jay Cutler, signed this week out of retirement in the wake of the injury to starter Ryan Tannehill, tossed the ball around before the game but did not play. Brandon Doughty received the meat of the first-half snaps and results were mixed. Third-stringer David Fales provided the most excitement, connecting on a 99-yard score in the fourth quarter.

When it was starters vs. starters, the Dolphins looked…: No bueno (not good), as we like to say in Miami. However, it was tough to get a gauge on Miami's starting offense without four starting linemen and the projected starting quarterback. The first-team offense had three snaps. Defensively, the Dolphins got roasted in their only series against Atlanta's starters, allowing an easy touchdown pass from QB Matt Ryan to Devonta Freeman on the heels of a speedy five-play drive.

One reason to be concerned: Considering how little Miami's starters played, the biggest concern should be the status of McMillan, who was supposed to inject some much-needed speed and athleticism into the heart of Miami's defense. Coming into Thursday, he topped the depth chart at middle linebacker.

That guy could start: RB Kenyan Drake finally got some solid action, albeit with the team's second- and third-string offensive linemen. He displayed a nice combination of burst and power, tallying 21 yards in the first half on a healthy 5.3 yards per carry. Can he duplicate that type of efficiency alongside the first team?

Rookie watch: All eyes will be on McMillan's injury. Behind him at middle linebacker is Mike Hull, an undrafted player with one career start in his first two seasons.

Wide receiver depth: While Miami's dangerous trio of Jarvis Landry, DeVante Parker and Kenny Stills didn't get much burn, it gave us the opportunity to witness the progression of second-year wideout Leonte Carroo, who caught a 33-yard touchdown from Doughty in the second quarter. Gase gushed about Carroo after practice on Tuesday, saying he's playing "light years" faster than when he was a rookie.

Prep star: Damore'ea Stringfellow, who totaled 116 receiving yards on two catches (one of those grabs was that 99-yard touchdown strike from Fales), was a big-time recruit out of high school. The undrafted rookie from Ole Miss ranked as the No. 51 overall prospect in the Class of 2013 in the ESPN 300.