The New England Patriots made headlines when it shipped backup quarterback Jimmy Garoppolo to the San Francisco 49ers on Monday. The surprise of that move goes on two levels, though.

Apart from leaving the Patriots with one quarterback — for now — in Tom Brady, the trade also baffled plenty of observers as all it took for the Patriots to cough up Garoppolo was a second-round pick.

Speaking in a conference call on Tuesday, Bill Belichick tried to explain the reasoning behind the trade, per Josh Alper of Pro Football Talk.

“We probably had in my mind, in my opinion, the best quarterback situation in the league for the last 2.5 years,” Bill Belichick said. “It is just not sustainable given the way that things are set up. Definitely not something we wanted to walk away from and I felt we rode it out as long as we could. We’ve, over a period of time, explored every option possible to sustain it but, at this point, it felt like we had to make a decision. It’s a very complex situation on multiple levels. This is really the last window that we had and we did what we felt was best for the team.”

The Patriots didn’t have a lack of suitors for Garoppolo, as the quarterback had heard his name linked to several trade buzzes in the past, but all those rumors can stop now with the Niners winning the Garoppolo sweepstakes.

Garoppolo ‘s current contract will expire at the end of the season, which means San Francisco is committed to shoveling money down the quarterback’s pocket in hopes of keeping him in the Niners’ fold for years to come.