The out-of-contract 27-year-old was spotted on Monday touring St Kilda's training base at Moorabbin, less than a fortnight after his season with Adelaide ended.
Channel Seven chief football reporter and former News journalist Mark Stevens was able to reveal the gun defender was one of the Saints' main trade targets.
"He turned up (at Moorabbin on Monday) to reveal himself a shock visitor in many ways, Adelaide's gun intercept defender." Stevens told his nightly news bulletin.
"He had a tour through the facilities and also a medical.
"Now, the (Western Bulldogs) and (Melbourne) Demons have been linked to Keath, the Saints also clearly in the race up to their eyeballs. He's out of contract at Adelaide, two years on offer there, perhaps could get four here at Moorabbin."
Keath's Adelaide captain Taylor Walker responded yesterday morning, acknowledging the time was now for Keath to find a lucrative contract, as well as explore his right to play in his home state.
“I think it’s part of the landscape,” Walker told Triple M Adelaide..
“He wants to assess his options and I suppose for Alex, he’s 28 this year and it’s probably one of his final contracts.
“So he’s probably looking for the best contract he can get … whether it be here or somewhere else, that’s up for Keathy to decide.”
Since debuting with the Crows in 2017, Keath has racked up 30 senior games including 18 this year, at times in All-Australian form in his key defensive post.
A latecomer to football after pursuing his cricketing dream, Keath was a Category B rookie signing of Adelaide's in 2015, meaning he remains a relatively inexperienced player despite his ripe age.