Yes, and probably fear of small turnout.
This poll was released prior to his announcement.
in part:
As far as President Trump and Governor DeSantis, Florida voters disapprove of their handling of the pandemic, according to the poll. 57% of voters said they disapproved of DeSantis's response to the coronavirus outbreak, while 59% said they disapproved of Trump's response.
Florida voters also mostly disapprove of DeSantis and Trump's school reopening plans: 56% disapprove and 37% approve DeSantis's handling of reopening schools, and for Trump, 59% disapprove and 36% approve.
According to Quinnipiac, DeSantis's job approval is at 41%, its lowest since his taking office in 2019. Trump's approval rating in the state is also down 5 percent points from where it was in April.
Looking forward to the 2020 election, 51% of Florida voters say they will back Biden, while 38% say they will vote for Trump.
In the April poll, Biden had gotten 46% and Trump 42%.
http://www.nbcmiami.com/news/local/latest-quinnipiac-poll-shows-desantis-approval-at-new-low-biden-leading-over-trump/2266650/