The former undrafted free agent reunites with Matt Eberflus.

Jack Sanborn, who joined the Chicago Bears as an undrafted free agent has signed with the Dallas Cowboys, according to reports.

Jeremy Fowler of ESPN had it first.

The linebacker was a restricted free agent, having just three years of accrued service in the league. But the Bears declined to tender him a restricted free agent deal, allowing him to sign with any team at the start of free agency.

Sanborn, undrafted out of Wisconsin in 2022, soon earned a starting spot on the Bears. He went on to appear in 48 games with 19 starts over the last three seasons.

He tallied 164 tackles, 4.5 sacks, 14 tackles for loss and one interception in Chicago.

Joining the Dallas Cowboys means a reunion with former Bears head coach Matt Eberflus, who is the defensive coordinator in Dallas. And he reunites with his position coach in Chicago, Dave Borgonzi.

Sanborn, a native of suburban Lake Zurich, became a fan favorite over his three seasons.

Source: Free-agent linebacker Jack Sanborn plans to sign with the #Cowboys on a one-year deal.

Reunited with Matt Eberflus and Dave Borgonzi, who coached him for three years in Chicago on his way to 164 tackles, 14 for loss. pic.twitter.com/IgcKzB0fXr

— Jeremy Fowler (@JFowlerESPN) March 12, 2025