Allardyce has made it clear to majority shareholder Farhad Moshiri that he doesn't see the 32-year-old in his plans going forward, which was why the former England captain was given permission to talk to DC.
With Manchester United, Rooney was 2010 Footballer of the Year and won five Premier League titles.
It is understood Rooney has been offered a contract until the end of the 2020 MLS season.
"Of course, he will bring the attention that MLS needs to attract more people to steal from the other sports that normally the American people are in love with".
Click through the gallery above to see five former EPL stars now playing in the MLS.
Earlier this week, Allardyce said he wanted England's and Manchester United's record goalscorer to see out the final year of his contract next season and added: 'There have been rumours about Wayne going overseas, China or America.More news: Huddersfield safe, but Chelsea suffer blow to Champions League hopes
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"There have been rumours about Wayne going overseas, China or America".
Rooney was reportedly close to moving to MLS at the end of last season, but instead rejoined Everton at the end of a 13-year trophy-laden spell at Manchester United.
Rooney is the club's top scorer this season with 11 goals but, as an indicator of where he is and where the club's form is, he has not scored since December 18.
Moyes predicted Rooney will go on to be an MLS success story if he completes a move to DC United that is reported to be worth around £12million.
"Only when I speak to him today I'll find out where the situation lies".
"If the player wants to go - if any players want to leave - I'm comfortable".
Allardyce has played him in a midfield role in the second half of the season in an attempt to inject some creativity into the team but that has impacted on the player's personal form, leading to growing frustration.