The 28-year-old is out of contract at the Championship club at the end of the season and is attracting plenty of interest from the Premier League.
Newcastle, Southampton and West Ham are all showing an interest in him - and now Tottenham have joined the chase for his signature.
Spurs boss Antonio Conte is eyeing up a new 'keeper with Hugo Lloris still yet to sign a new deal and reportedly keen on a move to boyhood club Nice.
Alex Crook revealed on talkSPORT on Thursday: "Sam Johnstone very much wants to be part of England's World Cup plans - I think he knows to achieve that he has to be back in the Premier League sooner rather than later.
"I'm hearing Tottenham are joining the likes of Newcastle, Southampton and West Ham in showing a definite interest in Sam Johnstone.
"Hugo Lloris is out of contract himself in the summer, he hasn't agreed a new one and as of January 1st he can sign a pre-contract agreement with overseas clubs.
"I am told Antonio Conte does want to keep hold of Hugo Lloris but it would be foolhardy not to look for alternative options.
"I know Antonio Conte isn't convinced by Pierluigi Gollini - the goalkeeper who they signed from Atalanta in the summer. I don't think they will be taking up the option to make that permanent.
"Sam Johnstone is very much on Tottenham's radar."
Johnstone came through Manchester United's academy but failed to make a first-team appearance at Old Trafford.
After numerous loan spells, he joined West Brom in 2018 and has been an impressive performer for the Baggies.
He was among their most consistent players as they were relegated from the Premier League last season and has earned three England caps.
Now he looks bound for a return to the Premier League ahead of the World Cup at the end of 2022.