Er, that would be "Teddy," a mascot from the Washington Nationals franchise.
Earlier this week, the Nats celebrated "HHS Night" at the ballpark for employees of the Department of Health and Human Services and Secretary Kathleen Sebelius. According to the Wall Street Journal, the Nationals franchise has no official partnership with the government to promote Obamacare. An HHS spokeswoman clarified that Roosevelt's participation was just part of the group celebration.
"Teddy" may not be the most popular of the team's presidential mascots, but he scored a starring role in a new video promotion shown just prior to the game. In it, he can be seen signing up for his shiny new Obamacare health insurance plan, as well as phoning the HHS helpline for info.