Miami Dolphins linebacker Raekwon McMillan's rookie season is over before it started.

The Dolphins learned on Friday that McMillan, the team's second-round pick in this year's draft, tore his ACL during the team's first preseason game Thursday evening. He is expected to miss the entire 2017 season.

Dolphins coach Adam Gase did not yet know the severity of the injury when asked about it during his postgame press conference.

"Nobody's told me anything yet so you guys seem to have better sources than I do and I'm the head coach so I don't know," Gase said. "We were talking about how he was possibly going to have to be on that [special] team. We knew we had to get him some reps at it, especially in a game. It's just tough to see a young player go down and not knowing what happened."

South Florida Sun-Sentinel reporter Omar Kelly spotted McMillan using crutches after the game, an early indication of just how severe the injury wound up being. McMillan didn't even get to play a defensive snap in the first preseason contest, as the injury occurred while he was covering a punt and he left the game before ever getting the opportunity to play defense.

With McMillan out for the year, the Dolphins lose a player they thought would be an important contributor for their defense. They'll have to depend more on Lawrence Timmons and Kiko Alonso, as well as expected backup Mike Hull