For players who were playing football

It is time to start throwing. You need to work on: proper warm-up, long toss and getting your body in shape for baseball season.

Here is a “List of athletes who played in Major League Baseball and the National Football League”
From Wikipedia, the free encyclopedia

This is a list of athletes who played in Major League Baseball and the National Football League. Fewer than 70 athletes are known to have accomplished the feat. The list includes two Heisman Trophy winners (Vic Janowicz and Bo Jackson)[1] and seven members of the Pro Football Hall of Fame (Red Badgro,[2] Paddy Driscoll,[3] George Halas,[4] Jack Spohn,[5] Ace Parker,[6] Jim Thorpe,[7] and Deion Sanders).[8] However, none of the players on the list has been inducted into the Baseball Hall of Fame. Check out the entire story here