The Patriots drafted Gronk and Edleman because the Jets traded for Brett Favre

In 2008, The Packers traded QB Brett Favre to the New York Jets for a conditional draft pick. Favre took the required majority of the team's snaps at quarterback but the Jets failed to qualify for the playoffs so the Packers received the Jets' 3rd round pick (3–83).

During the 2009 NFL Draft, The Packers traded picks 2–41, 3–73 and 3–83 to the New England Patriots for picks 1–26 and 5–162.

The Packers then drafted Clay Mathews (26) & Jamon Meredith (162).

The Patriots then drafted Darius Butler and Brandon Tate instead of Clay Mathews. We also had another 3rd round which we traded to Jacksonville for a 7th in '09 and a 2nd in '10. With the 7th rounder we drafted Julian Edelman. With the 2nd rounder in '10 we threw in a 6th rounder to trade up 2 spots with the Raiders and drafted Rob Gronkowski. Wow.

TL;DR - The Patriots got Gronk and Edleman as a result of the Packers trading Brett Favre.

The Jets directly caused the Patriots to get Gronk and Edleman.