MIAMI -- The first half of the season has been a roller coaster for the Miami Dolphins. The first eight games have been a mix of quality victories and disappointing defeats, but Miami reaches midseason on the upswing after winning three straight games.

The Dolphins (5-3) are trying to end a six-year playoff drought and could do so with a similar second half of the season. Miami is gaining consistency at the right time, given a challenging November and December schedule.

Midseason MVP: Receiver Mike Wallace is having an impressive second season in Miami. He leads the team in receptions (35), yards (468) and touchdowns (five). Wallace has been the most consistent player on offense, which is why he gets the early nod for MVP honors. Wallace has scored at least one touchdown in five games this season, and he's on pace to tie his career high for touchdowns in a season (10). Quarterback Ryan Tannehill has yet to connect with Wallace on the deep ball, which has been an issue. Wallace can be even more dangerous if Tannehill can be more consistent with his deep passing in the second half of the season.

Biggest disappointment: The Dolphins had high expectations when they signed veteran running back Knowshon Moreno in free agency. Moreno was coming off a career year with the Denver Broncos; he recorded his first 1,000-yard season and helped lead Denver to an AFC title. But Moreno struggled to stay healthy from the moment he stepped foot in Miami. It started with a nagging knee injury in the spring that required a cleanup procedure. Then Moreno suffered an elbow injury in Week 2 of the regular season and a season-ending knee injury in Week 6. Moreno had just 148 rushing yards. With the mileage and wear and tear on his body, it's unlikely Moreno will return to Miami when he becomes a free agent next March.

Best moment: This is a tough call. The Dolphins started the season on a high note, with a 33-20 home victory over the reigning AFC East champion New England Patriots. That showed right away that Miami has the talent to compete with anyone. But Sunday's 37-0 victory over the San Diego Chargers overtook Week 1 as the biggest moment of the season. Miami pounded another playoff contender from start to finish and picked up its first shutout win since 2006. The Dolphins won their third game in a row for the first time this season and earned an emotional victory for head coach Joe Philbin, who missed two days last week after the death of his father.

Worst moment: Miami's worst moment in the first half of the season didn't involve a game. Philbin created an unnecessary quarterback controversy leading into a Week 4 matchup against the Oakland Raiders. Philbin refused to name the starting quarterback during the week, which caused national headlines and speculation Tannehill was close to being benched. Even Tannehill admitted he was bothered by Philbin's approach, and the quarterback said it was the toughest week of his career. Tannehill responded with one of his better games of the season in a win over Oakland and has mostly played well since.

Key to the second half: The Dolphins will only go as far as Tannehill can take them. Miami is 4-1 when Tannehill produces a passer rating of 80.0 or higher and 1-3 when he posts a passer rating under 80.0. The Dolphins have their most talented roster in years, and it is much easier to win when Miami gets solid and consistent play from Tannehill. Yet when the quarterback play is inconsistent, there is little margin for error for the rest of the team. In order to make a playoff push, Miami needs to find a way to get the best out of Tannehill on a weekly basis.