What happened: Indianapolis pledged its support for Chris Johnson and invited another participant to step forward. The Titans joined the campaign earlier this month.
Why it matters: The Colts' participation extends an NFL-led push for ALS awareness and research funding. Johnson revived the challenge after disclosing his ALS diagnosis in June.
By the numbers: The original campaign raised an estimated $135 million in the United States, part of $220 million worldwide.
What to watch: More NFL teams and players could answer Indianapolis' open invitation.