The news was first reported by Politico.
The super PAC's decision follows news that the Democratic Senatorial Campaign Committee had again delayed its own ad buy in Florida, where polls show Rubio sporting a sizable lead over the two-term congressman. Murphy allies feared that the DSCC would not spend at all on the race.
Party strategists say the decision to not invest in Florid is in large part a consequence of how expensive it is to run TV ads in the mega-state of 20 million people and 10 media markets, especially against an incumbent with universal name identification.
Groups like the DSCC and the Senate Majority PAC can choose instead to spend in battleground races like North Carolina, Missouri, and Indiana for as much as it would cost to compete in the Sunshine State.