The Miami Dolphins are halfway through their exhibition games as we get closer to the regular season in September. Miami lost to the Dallas Cowboys 41-14 in a game with a lot of teaching points for the Dolphins.

With that in mind, here is a look at whose stock is rising and falling this week in Miami:

Rising

1. Ryan Tannehill, quarterback: Tannehill was more confident, comfortable and efficient in his second preseason game. He threw for 168 yards and two touchdowns. Tannehill’s stats would have been even better if not for three drops by his receivers. Partial credit also goes to Miami’s offensive line, which gave Tannehill plenty of time to get to his second and third reads. This was a good step in the right direction.

2. Kenny Stills, receiver: Stills was locked in Friday. He caught a 55-yard deep ball on the second drive and a pair of touchdowns in the first half. Stills finished with three receptions for 71 yards. Dolphins head coach Adam Gase said Stills has been one of the hardest workers on the team this offseason, and it’s showing up on the field. If Stills plays this well during the regular season, Miami will have a potent and dangerous group of receivers.

3. Isaiah Pead, running back: There will be some interesting roster decisions at running back in the coming weeks. Only three or four will make the final cut, and Pead is made his case with 48 rushing yards and a reception for 30 yards. Pead is battling Damien Williams and Daniel Thomas for backup jobs this season.

Falling

1. Defense: Where do you start with this one? The Dolphins' defense overall was awful Friday against Dallas. The Cowboys scored 27 points in the first half against Miami’s first- and second-string defenses. Those are the players who will contribute for the Dolphins this season. They also allowed Dallas rookie quarterback Dak Prescott to look like a star with 199 passing yards and four touchdowns in limited playing time. Poor tackling, poor coverage, poor run fits ... there are a lot of teaching points in this game for Dolphins defensive coordinator Vance Joseph and Gase.

2. Cornerback: This has been an area of concern for Miami since training camp began. Dallas quarterbacks Tony Romo and Prescott had 107.5 and 158.3 passer ratings, respectively, as the Dolphins’ secondary failed to stick to receivers. No. 1 cornerback Byron Maxwell was beaten several times by Cowboys receiver Dez Bryant, including on a 28-yard touchdown pass. Tony Lippett and Bobby McCain also struggled with their assignments. Help could be on the way. Second-round pick Xavien Howard was taken off the physically unable to perform list and is expected to return to practice this week.

3. Jordan Cameron, tight end: The Dolphins keep waiting for the former Pro Bowl tight end to click, and it remains a work in progress. Gase made a point to get Cameron involved in the offense through his play calling. The first play of the game was a designed pass to Cameron for 5 yards. The second play was a slant and it would have been a touchdown if Cameron hadn't dropped the ball in the end zone. The tight end historically plays an important role in Gase’s offense. Miami needs Cameron to turn the corner sooner rather than later.