“The timing is driven more by him recognizing he can’t wait too long,” says a Republican operative familiar with his thinking. “If he decides to run for president, there is a high quality bench for Republicans in Florida. It’s not like the party needs to spend a lot of time recruiting people.”

Republicans in the state and in Washington appear confident that Rubio’s self-imposed springtime deadline gives them enough time to build up a replacement candidate. They are also comforted by the likelihood that Democrats won’t officially enter the race until they know whether the incumbent will be in it.

But there’s another scenario that some in the state are starting to envision, one that may give other possible candidates pause. The filing deadline for anyone seeking Florida’s U.S. Senate seat isn’t until May 2016. Theoretically, Rubio could run for president until his state’s March 1 primary (or even after), and re-evaluate the Senate option if his White House bid has failed by then. (The primary for all other offices takes place Aug. 30.)

“He will still have time to get back into the Senate race if none of the Republicans have caught fire,” says the Florida Republican strategist. “That’s a big calculation for the Republicans in deciding to run. What happens if you get into this race and at some point, Marco comes back in and pulls the rug out from the field?” And if a Democrat catches fire and looks to be outpacing Republicans, the strategist said, “you’re going to see a ton of Republicans call on Marco to come back.”