 On 26 December 2015, the 49ers promoted Hayne to the 53-man roster again after placing guard Alex Boone on their injured reserve list.Hayne announced his retirement from the NFL on 15 May 2016, and joined the Fiji sevens team in hopes of playing in the 2016 Summer Olympics in Rio de Janeiro.He later explained that he retired due to not wanting to learn a new playbook, as the 49ers had hired Chip Kelly to be their new head coach for the 2016 season.