Tuesday turned out to be clean-up day in the NFL.

The Houston Texans admitted a mistake when they released safety Ed Reed after nine non-impactful games. The San Francisco 49ers thought Kyle Williams could get them through their injury problems at wide receiver, but they released him.

November is a time to evaluate the moves, or non-moves, of the offseason. What were five of the biggest mistakes made this offseason?

1. The Cowboys going to the Cover 2: Monte Kiffin is one of the most impactful assistant coaches of his era. He helped make the Cover 2 defense a strategy that got franchises to the Super Bowl. His resume has been impeccable. But moving the Cover 2 to Dallas has turned into a historically bad decision. No team has given up an average of more than 300 passing yards a game through an entire season. The Cowboys are giving up 313 passing yards a game and have lost middle linebacker Sean Lee for 3-4 weeks with a hamstring injury. Following Sunday night's 49-17 loss to the New Orleans Saints, owner Jerry Jones said his firing of defensive coordinator Rob Ryan "doesn't look good right now." The Saints put up 625 yards on the Cover 2. Kiffin isn't getting fired, but he's only on a one-year contract and it's not like the Cowboys can promote Rod Marinelli to take the job. Marinelli is loyal to Kiffin and would reject being an interim coordinator. Jones wanted turnovers in making this change. The turnover to the 4-3 has resulted in 12 interceptions, but the Cowboys have given up 20 touchdown passes.

2. The Dolphins neglecting the backfield: General manager Jeff Ireland was the league's biggest spender this offseason. He invested heavy to build around quarterback Ryan Tannehill by adding Mike Wallace, Brandon Gibson and Dustin Keller. He swapped older, run-stopping linebackers for better blitzers in Dannell Ellerbe and Philip Wheeler. He let two corners go and gave their positions to Dimitri Patterson and Brent Grimes. Aside from all the problems in the locker room, the Dolphins' biggest mistake was letting Reggie Bush walk and not having anyone ready to replace him. Bush is one of the reasons the Detroit Lions jumped from 4-12 to atop the NFC North. The Dolphins are averaging 87 rushing yards a game and have had three games in which they've been held below 25 yards.

Because of injuries and a lack of depth, Anquan Boldin has been the 49ers' only reliable wide receiver this season. Cary Edmondson/USA TODAY Sports

3. The 49ers neglecting the receiver position: Coach Jim Harbaugh was confident enough with his system that he thought he could get by until Michael Crabtree and Mario Manningham came off the physically unable to perform list. The 49ers did well by getting Anquan Boldin, but the inability to add more has resulted in Colin Kaepernick's passing numbers to drop dramatically. Williams and Marlon Moore have been released. They contributed only 13 receptions. They traded for Jon Baldwin, but he has only three catches and spends his time on the inactive list. The offense hits a breaking point when tight end Vernon Davis goes down. When he's out, there is no pass-catcher who can get separation from a defensive back. Rookie tight end Vance McDonald has only six catches. Wide receivers not named Boldin have 20 catches in nine games. No wonder Kaepernick is completing only 56.4 percent of his passes and the 49ers are netting only 173.9 yards a game through the air.

4. The Ed Reed move: The Texans knew with a tight cap it was going to be tough to re-sign Glover Quin at the beginning of free agency. Quin got $4.7 million a year and is doing well in Detroit. To replace him at safety, the Texans gave Ed Reed a three-year, $15 million deal. It didn't work out. Reed came with a hip injury and left with a termination notice nine games into the season. Even though he was healthy Sunday, Reed was stripped of his starting job, used as a backup and was in for only 12 plays against the Arizona Cardinals. The Reed signing isn't the reason the Texans are 2-7, but it was a big-name move that didn't work out.

5. Teams getting caught short at backup QB: This is a list that will grow during this second half of the season. You start with the Buffalo Bills. EJ Manuel surprised everyone at camp with the look of being a decent young starting quarterback. But he missed preseason time with a knee injury. Another knee injury tested the Bills' backup situation. They shouldn't have let Tarvaris Jackson go in the spring. They entered the regular season with Jeff Tuel, an undrafted rookie, as the backup and then went to Thaddeus Lewis, who was on the practice squad. Some people outside of Green Bay wondered if Graham Harrell had the arm strength to back up Aaron Rodgers. The Packers gave up on Harrell and brought in Seneca Wallace, who went on injured reserve Tuesday. Scott Tolzien is now the starter. The Packers are fortunate the Bills released Matt Flynn, who was signed to be Tolzien's backup until Rodgers is healthy.

From the inbox

Q: Has the NFL reached its peak? With so many players injured this year and the rate of attrition of starting QBs lost for several games, if not the season, has the NFL reached the point that the game is no longer playable for long stretches by many skilled players? At this point, the teams that retain their starting QBs and a semblance of a healthy offensive line will make the playoffs. That just might be about four or five teams considering how many QBs are getting injured every weekend. (OK, so maybe I am exaggerating, but not by much.) The Lions got away with late hits on Jay Cutler and injured him. While the hits Peyton Manning took from the Chargers were legal, he is facing possible injury time. Jake Locker is out. Aaron Rodgers is out. Green Bay is using its third-string QB. The Eagles lost Michael Vick (for better or worse). Buffalo has a merry-go-round for QB due to injuries. RG III has not been the same from his injuries last year and the hits he is taking this year. How can teams hope to maintain any competitive edge when you have whole lines missing? Is it not time to increase roster size?

Daniel in Denver