MLS chief Don Garber says he has grown 'cautiously optimistic' about the season returning.

Players have returned to training this week in MLS.

"We're more optimistic about what a return to play plan could look like. I think a month ago we were very pessimistic," Garber said.

"I think our country has done a pretty good job of flattening the curve, which is what the objective was. We need to be mindful of and focused on continuing to follow local guidelines because flattening the curve requires us all to be very focused and committed to all the guidelines local health authorities set out.

"So I would say we're cautiously optimistic."