A think some on BBI are making a mistake to believe that its great news that Garrett and Callahan worked together and that their futures include working together on the Giants new coaching staff.
A few facts:
Callahan was successful for the 2012 season as the Cowboys O Line coach and running game coordinator, though the team finished 8-8.
During the offseason, Jerry Jones announced that he wanted Garrett more involved in game management, and Jones announced that Callahan would be calling the plays for the 2013 season. The Cowboys again finished 8-8.
In January 2014, Garrett hired his very good friend, Scott Linehan, to be the Cowboys passing game coordinator. Callahan was informed that play calling duties would now become Linehan's.
With the hiring of Linehan in January of 2014, Callahan advised the Cowboys that he had an opportunity to interview to become the Offensive Coordinator for the Browns. The Cowboys blocked him from interviewing.
Callahan was then approached by the Baltimore Ravens, again to interview to be their Offensive Coordinator. He was again blocked from interviewing by the Cowboys.
Callahan stayed on with the Cowboys, but left when his contract expired on January 14, 2015.
On January 15, 2015, Callahan joined the Redskins.
We don't know what Joe Judge's plan is for hiring his offensive coaches, but I thought it helpful to show a timeline.
Personally, I find it hard to conclude that a Garrett/Callahan reunion is coming to New York.