This is happening.
Ex-NFL receiver Chad Johnson has not played in the league since February 2012, catching one pass for the New England Patriots in Super Bowl XLVI. Johnson spent training camp in 2012 with the Miami Dolphins but was released before the regular season began.
Eight years later, Johnson announced on his Twitter account that he was trying out for an XFL team as a kicker:
Johnson has been a receiver his entire career in the NFL, however back in Week 2 of the 2009 preseason, as a member of the Bengals, he converted an extra point and then booted the subsequent kickoff due to an injury to starting kicker Shayne Graham.