Here’s a look at the first half of the season for the Buffalo Bills (4-5) and a preview of what to expect in the second half:

Grade C: The Bills have earned an average grade for their average performance so far this season. They deserve praise for a four-game winning streak from Weeks 3 through 6 that rocketed them to No. 8 in ESPN's NFL Power Rankings. Injuries slowed down the offense in the ensuing weeks, while Rex Ryan's defense has looked decidedly mediocre. The Bills are on a path to another 8-8 season, which might earn them another average "C" grade, but in reality, it would be a failure for a team that had the talent to do bigger things.

Midseason MVP: RB LeSean McCoy. During the Bills’ four-game winning streak, McCoy’s play put him the conversation for NFL MVP. He was the NFL’s second-leading rusher through Week 6 and was inarguably the key cog to an offense that was operating without injured top receiver Sammy Watkins. After being severely limited by a hamstring injury in a Week 7 loss to the Dolphins, McCoy sat out another loss to the Patriots to get healthy and the time off appears to have gotten him back on track. He gained 120 total yards in Monday night's loss to Seattle.

Best moment: Beating the New England Patriots in Week 4. The Bills shut out their division rival 16-0 for only their second win at Gillette Stadium since the facility opened in 2002. It's easy to point to the Patriots starting quarterback Jacoby Brissett and discount the Bills' performance, but that wouldn't tell the whole story. The Bills physically dominated a mostly healthy Patriots defense for the first three possessions of the game, gaining at least 66 yards and scoring each time. That was all the offense needed for the day.

Worst moment: Losing to the Patriots in Week 8. Ryan was riding high after his Oct. 2 victory in Foxborough, Massachusetts, but cautioned fans that things might be different when Tom Brady arrived at New Era Field four weeks later. He was right. Brady tore apart Ryan's defense -- playing with most of its key pieces -- for 315 passing yards and four touchdowns before being pulled from the blowout in the fourth quarter. It was the second consecutive season that Brady lit up the Bills on their home field, and it was another embarrassment for Ryan's defense.

Player to watch: WR Watkins. The Bills were so desperate for help at receiver that they lured Percy Harvin out of retirement to re-sign with the team last week. Injuries have hit nearly every receiver on the Bills' roster, most notably Watkins. He is eligible to return to practice Friday, but it's unclear when the Bills' medical staff will allow him to hit the field again on his surgically repaired foot. Watkins is eligible to return from injured reserve to play as soon as the Bills' Nov. 27 game against Jacksonville.

Second-half outlook: The Bills play all seven of their remaining games against the AFC, which is important given that Buffalo has a 1-4 record against conference opponents. Ryan has already conceded that the Bills won't catch the Patriots in the AFC East race, which makes the two wild-card spots the Bills' only path to the playoffs. Edging out other teams in the hunt could require winning a tiebreaker, and that's when the Bills' early-season AFC losses to Baltimore, the Jets and Miami have potential to haunt them. The streaky Bills will need to get hot again and finish 10-6, or better, to earn their first postseason berth since 1999.