Here are five storylines to watch Thursday night, when the Baltimore Ravens play at the Miami Dolphins in their second preseason game:

1. Ryan Mallett gets a stronger supporting cast. Mallett, who continues to fill in for Joe Flacco (back), is looking to bounce back after a rough preseason opener. He completed half of his passes (9 of 18) and averaged a dreadful 3.2 yards per attempt. Mallett continues to lack touch, missing wildly on his throws downfield. Thursday night should be a better evaluation because his top two receivers (Jeremy Maclin and Mike Wallace) are expected to play, along with running back Danny Woodhead.

2. Defense looks to build on dominating cameo. The Ravens will face Jay Cutler in his first game with the Dolphins, and they'll look to dominate just like they did last week against Kirk Cousins. Baltimore stifled Washington's first-team offense to the tune of minus-1 yard on six plays. "We have not proved anything yet," defensive coordinator Dean Pees said. "We played good for three series. That is what we have proven. We are so far away from being where we need to be to play a season and really be the kind of defense that we want to be."

3. Marlon Humphrey makes his debut. The rookie first-round pick has been impressive with his composure and aggressive play. Humphrey, drafted No. 16 overall, will try to carry over that strong camp into his first game. (He didn't play in the preseason opener because of an undisclosed injury.) "It will be fun to see," coach John Harbaugh said. "He has had another good week of practice. Seeing the game reps will be a big step for him."

4. Who will take the lead at returner? Tim White was Baltimore's primary returner until the undrafted rookie suffered a season-ending thumb injury in the preseason opener. It looks like the competition will be between Michael Campanaro and Keenan Reynolds. Campanaro averaged 12.6 yards per punt last season, and Reynolds broke a 46-yard punt return. "I think coach Jerry [Rosburg, the special-teams coordinator/associate head coach] knows he can trust me back there -- just fielding the ball and making plays," Campanaro said.

5. Offensive line continues to shuffle. The Ravens' blockers up front remain in flux. There will be different players at four of the five positions along the line. Left tackle Ronnie Stanley is out with an undisclosed injury, and right tackle Austin Howard gets in his first game with Baltimore. Pro Bowl right guard Marshal Yanda (offseason shoulder surgery) is expected to play after sitting out the preseason opener, and Matt Skura shifts from right to left guard. Only center Ryan Jensen will be at the same spot for the first two preseason games. "Sure, we would rather have them all set and working on their spots," Harbaugh said. "But that has not been the case. That is just the way it has worked out at that position."