Cincinnati Bengals: Failing to Trade for Semaje Perine
Although this deal is probably the smallest one on the list, that is why it should be so frustrating for Bengals fans. While the Bengals don't have a ton of holes, one of their biggest weaknesses is their running game. Joe Mixon has been solid, and even in this scenario would still be the starter, however, there is no depth at all behind him.
Enter Samaje Perine, who was a key piece of the Bengals team last year, but left for a more lucrative contract in Free Agency with Denver. Perine has fallen behind Jaleel McGlaughlin on the depth chart in Denver, and the team was reportedly listening to trades for anyone on their roster, so they undoubtedly would have traded Perine, and it likely wouldn't have cost more than a late Day 3 pick.
Perine would've provided the Bengals with insurance at the running back position in case Mixon was to get hurt, while also giving them someone who can spell Mixon to keep him fresh like he did last year. This would've not only made Mixon look better in his opportunities but also would provide Cincinnati with more depth which is always key as the year moves along.
The Bengals are in win-now mode and entered the year as a Super Bowl favorite, so it was shocking to see them not make any moves, after a slow start. Failing to make such a low-risk move for a player that the team has familiarity with was a huge mistake for the Bengals and one that they will regret big time if Mixon were to get hurt at any point in the second half.