If Spicer leaves the job anytime soon, his tenure will be historically short. Each of the five men who held the position for less time than Spicer had his run cut short by special circumstances.
Roger Tubby (33 days) and Jake Siewert (111 days) were post-election fill-ins under lame-duck presidents — Harry Truman and Bill Clinton, respectively.
Jonathan Daniels (19 days) had just taken over for the iron man of press secretaries, Stephen T. Early (4,403 days), when Franklin Roosevelt died in office. Harry Truman briefly brought back Early on an interim basis before naming his own press secretary, Charles Ross.