Star-studded lineup will take to the streets of Boston later this month.
He defeated Gebre Gebremariam last year in the inaugural edition.
Forecasted temperatures for Monday's race are in the 80's.
The invited athletes met with the press on Friday.
Four-time Boston Marathon champion Bill Rodgers continues to inspire American runners.
Deep international fields highlight the 116th running of the world's oldest annual marathon.
Defending champions will face strong competition on April 16.
Geoffrey Mutai ran the fastest unofficial marathon there last year.
The reigning Boston Marathon champ has some doubts heading into this weekend's race.