Head coach Bill Belichick faced that question Friday following the Patriots' release of the veteran wide receiver Thursday.
"It’s just one of those things that just didn’t work out," Belichick told reporters in a video press conference. “I have a lot of respect for Mo. But ultimately, things just didn’t work out."
Sanu suffered an ankle injury in Week 10 last season -- his third game in New England -- that limited his effectiveness down the stretch and required offseason surgery. The 31-year-old trained relentlessly this spring and summer to regain his form but apparently didn't show the Patriots enough to justify paying him $6.5 million this season.
"I think he tried very hard,” Belichick added. “I think we tried hard. I don’t think it was anybody’s fault or anything like that. It was just one of those situations that just didn’t work out as well as I think everyone hoped it would have when the transaction was made.
"As always, we’ll try to make the decisions that we feel are best for the football team, whether that’s bringing a person in or releasing a player. Obviously, it can go both ways. At this point in time, we felt (releasing him) was best for the team. Last year, we felt differently. We’re in a little different situation this year."
That's a pretty candid answer by Belichick's standards, and it's a sign the head coach very much hoped Sanu could succeed in New England.
Instead, the Sanu trade will go down as one of Belichick's biggest blunders after the wideout caught just 26 passes for 207 yards over eight games with the Patriots.