DAVIE, Fla. -- The Miami Dolphins' first full day of rookie camp is officially in the books.

Here are some observations from Friday's two-a-day practices:

The two rookies who impressed most on the first day were wide receiver DeVante Parker and cornerback Bobby McCain. Parker was fluid and made several impressive catches and was the best player on the field. That was expected from Miami’s first-round pick, and you saw early flashes of why he was taken No. 14 overall. McCain was more of a surprise. He's an undersized cornerback who was taken in the fifth round. But he covered well on his first day and showed some aggressiveness, competitiveness and the ability to stay around the football. It’s only one day, but McCain could be a sleeper to keep an eye on.

Dolphins fifth-round pick Tony Lippett has a ways to go in his full-time transition from college receiver to NFL cornerback. He has the size and measurables. But Lippett’s technique wasn't up to par in Miami’s first two practices. Lippett was beat by several receivers in drills Friday. He did get one interception in one-on-one drills. Dolphins coaches will spend a lot of time with Lippett to get him up to speed this offseason. “We looked at all of the attributes. ... At the end of the day, we just thought this guy has potential,” Dolphins head coach Joe Philbin said. “We really liked him. We wanted to work with him.”

I didn’t know of receiver Tyler McDonald before Friday's practices. But he certainly caught my attention by making consistent plays. McDonald, who is 6-foot-3 and 190 pounds, consistently found ways to get open. Was it one good day or can McDonald keep it up?

For Dolphins fans interesting in jersey numbers, Parker is No. 11, fourth-round pick Jamil Douglas is No. 75, McCain is No. 28, Lippett is No. 36, defensive tackle Jordan Phillips is No. 97 and running back Jay Ajayi is No. 33.