Mohamed Sanu to the Patriots for a second-round pick in 2019
In what would be Tom Brady's final season suiting up with New England, the Patriots started the season with what could have been one of the best receiving corps they had in years.
It was led by Brady's go-to guy Julian Edelman and followed by the unlikely addition of Antonio Brown after his release from the Raiders. Add in Josh Gordon, Jakobi Meyers, and the Patriots' offense seemed well put together for the season ahead.
Unfortunately, though, that didn't last long.
Because more allegations were made involving Brown, he was released from the team after just one game. And Gordon was invisible in all but one of the six games he played before being placed on injured reserve and being waived in late October.
That left Brady with 33-year-old Edelman, inconsistent Phillip Dorsett, and rookies N'Keal Harry and Meyers to carry the offensive load.
Since it was assumed that Brady was near the end of his career and winning was even more critical, Belichick made a trade shortly before the deadline for Atlanta Falcons receiver Mohamed Sanu, trading a 2020 second-round for the 30-year-old.
It wasn't the move most hoped for, as Sanu had been a decent player but never got past playing behind Julio Jones, making it feel like a high price tag for a receiver of his caliber.
His performance through the eight games he took the field for only validated that initial assertion.
During the half-season he spent in New England, Sanu totaled 26/47 receptions for 207 yards and one touchdown; far from the production the offense was needing and the type of weapon Brady was hoping for.
At the end of the season, he remained with the Patriots during training camp because he was still under contract through the 2020 season. But after being placed on the PUP list and not becoming what the offense needed, he was released a week before the start of the regular season.
Sanu's short stint in New England is one of Belichick's more memorable trade mistakes during his career. Not just because of the price to acquire him but also because he wasn't the game-changing player they needed then, making it make even less sense overall.