Northamptonshire’s Josh Cobb said he was “blindsided” by the decision to replace him as T20 Blast team captain and was “shocked and disappointed” by the news.
Cobb, 32, has been the Steelbacks’ white ball captain since 2019.
Willey is back on Wantage Road this summer for a second spell after spending eight years with Yorkshire.
Northants head coach John Sadler said the club wanted to “maximise” Willey’s “expertise” and make the most of the 33-year-old’s international and Indian Premier League experience.
Sadler added that Cobb “managed the team well” and had a “good cricketing brain”.
In a report on Twitter, Cobb said: “Having been blindsided by the news, I am shocked and disappointed to be relieved of my duties as captain so close to Blast’s departure.
“Spending the winter planning and preparing the team, I felt we were in a good position to take on the challenge this year and we absolutely are!”
Cobb added that it had been “an honor and a privilege” to have been captain before wishing Willey “all the best” as skipper.
Two-time Blast winners Northants start this year’s tournament against Worcestershire Rapids at Wantage Road on May 24.