Derby were remaining tight-lipped on Tuesday over reports they are finalising a move for former England captain Wayne Rooney.
News of the Rams' supposed interest in the 33-year-old emerged shortly before they opened their new Championship campaign with a 2-1 victory away at Huddersfield on Monday night.
Rooney has been linked with a possible player-coach role at Pride Park – where his former England team-mate Frank Lampard was given his first opportunity in management last year.
Pictures appeared on social media on Tuesday morning of Rooney at Heathrow airport having flown in from Washington DC, where he currently plays for MLS side DC United.
The Rams refused to confirm or deny Rooney was headed for talks with the Championship club when contacted by PA on Tuesday.
When asked about the links with the former Everton and Manchester United striker following Monday's win over Huddersfield, Derby boss Phillip Cocu was coy.
"I'm sorry, I can't say (anything). There are still three days and the market's open," said the Dutchman, who replaced Lampard earlier this summer after the former Chelsea midfielder returned to take charge at Stamford Bridge.
"I've said before that we're not done and we're working to get the team complete, but I cannot talk about any names at this moment.
"We have a lot of players we think could be an asset for the team, you try to get the best you can with resources you have at the club.
"A few more days and hopefully I can tell you something more."
Rooney joined DC United last summer on a three-and-a-half-year
contract after one season with boyhood club Everton.
Reports suggest a deal with Derby could be confirmed as early as Tuesday, with the Championship transfer window set to close at the same time as the Premier League's on Thursday at 5pm.
Rooney is England's all-time record scorer with 53 goals in 120 appearances, as well as Manchester United's record goalscorer with 253 goals in 559 appearances.