Worcestershire have given Yorkshire 28 days notice of approach to speak to Matthew Hoggard.
Hoggard, 32, is out-of-contract at Headingley Carnegie at the end of the season and is considering his options.
The Royals are looking for a potential replacement for Simon Jones, who has been ruled out of the entire 2009 season with persistent knee problems.
Hoggard played the most recent of his 67 Tests for England in March 2008.
Worcestershire have also made an approach to the Tykes for fast bowler Ajmal Shahzad.
Shahzad, 23, and Hoggard both appeared against Worcestershire in last week's LV County Championship match at New Road, but the formal approaches were made before that fixture.
Hoggard has been offered a two-year deal with Yorkshire but recently admitted his future may lie away from the county after being left out of the limited-overs side.
He is Yorkshire's leading wicket-taker in the championship with 15 wickets this season, while Shahzad has broken into the Yorkshire team this season.
Worcestershire, however, denied they have also made an approach to speak to Yorkshire's former England captain Michael Vaughan.
The county's chief executive Mark Newton said: "Yes, we have made approaches for Hoggard and Shahzad. But we have made no approach for Michael Vaughan."
Meanwhile, Yorkshire have joined Surrey in the race to sign Worcestershire's unsettled England one-day wicketkeeper Steve Davies.
Newton confirmed Worcestershire have received 28 days notice of approach for Davies from Yorkshire.
Davies has declined to put pen-to-paper on a new three-year deal offered by the Royals even though they have agreed the terms with his agent.
The 23-year-old has asked to keep his options open until the end of the campaign when his current deal runs out.