The former England captain has agreed a deal with the Major League Soccer side that could see him move to the USA.
Rooney has top-scored for Everton with 11 goals in his first season back at the club where he began his career, but hasn't been a regular starter in the second half of the season and often played in midfield.
"Certainly the deal is not done but obviously there is some interest from our end", Olsen told TMZ as he was exiting the airport in Washington.
The agreement, which runs to the end of the MLS season in 2020, is yet to be signed, but SSN understands it would take a significant change of heart by Rooney and his family to stop the transfer going ahead.
"I'm comfortable with any player who wants to leave but let's get this clear, Wayne Rooney hasn't asked to leave".
Of greater significance, however, is the fact that Rooney seems destined to leave the club for DC United in the summer. All I know is there is interest - where Wayne lies with it I can't tell you at the moment.
"But in terms of clarity of whether Wayne is staying or leaving, I'll find out a little more later when he comes into training".
There have been reports of a falling out between the former England manager and all-time England record goalscorer, with their relationship thinning throughout the duration of the campaign.
Everton fans are planning to voice their discontent at the way the club has been run this season during Sunday's game against West Ham at the London Stadium.
The 32-year-old is seeking clarification from the Everton hierarchy over the manager's situation and his future role before deciding his next step, but would prefer to remain at his boyhood club. "I don't want to create the headline".