The keeper, released by the Seasiders at the end of the season, could join Pool’s Championship rivals in the next week, linking up again with Simon Grayson.
It was Grayson who signed Rachubka for Blackpool in January 2007 and the American quickly established himself in the side which won promotion from League One.
He was an ever-present under Grayson, consistently chosen ahead of Matt Gilks.
It wasn’t until Ian Holloway arrived that Rachubka lost the No.1 spot. In the Premier League last season, the 30-year-old made just two starts and was hindered by knee injuries.
Pool had an option to keep Rachubka for a further 12 months but decided against it.
Several clubs, including Blackburn, are believed to have made inquiries but it is Leeds who are set to complete a deal.
Grayson needs a keeper to replace Kasper Schmeichel, who is on the verge of joining Leicester in a £1m-plus deal.
Holloway also needs keepers. Pool have also allowed Richard Kingson to go, and with Matt Gilks unlikely to take up the offer of a new contract, youngster Mark Halstead is the only stopper on the books.
The Seasiders have been linked with Croatian Vedran Runje, a 35-year-old keeper available on a free after he exercised a release clause in his contract following Lens’ relegation from Ligue 1 in France. However, The Gazette has been told Runje is not a target at this stage.
Derby striker Luke Varney, who spent last season on loan with the Seasiders, is reported to be the subject of a £750,000 bid from rival Championship club Portsmouth.