West Bromwich Albion have released 12 players ahead of the summer transfer window.
Midfielder Romaine Sawyers is another big name on the list of departures.
According to The Sun, Johnstone is now being tracked by several clubs in the Premier League.
His ex-team Manchester United, as well as Tottenham, are showing an interest in the 29-year-old.
A West Brom club statement said: "Three senior players will be leaving The Hawthorns this summer.
"Goalkeeper Sam Johnstone will depart having spent four years at the club, making 167 appearances since his arrival in July 2018.
"Sawyers made 64 appearances for the Baggies, scoring one goal against Cardiff City in October 2019.
"Striker Andy Carroll will also depart. The 33-year-old arrived in January and went on to make 15 appearances for Albion, scoring three goals."
Jamie Soule, Owen Windsor, Aurio Teixeira, Kevin Joshua, Zak Delaney, Mark Chidi, MacKenzie Lamb, Leon MacHisa and Daniel Ngoma have all been released.
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!