It matters if his QB style is similar or different than the starter. If you'll remember the McCoy vs. Ash debate, the points in Ash's favor rested a lot on his superior mobility (example: http://bleacherreport.com/articles/1307867-mack-brown-officially-names-david-ash-texas-starting-qb). Ash is a pretty mobile QB, so is Swoopes. Since they are stylistically similar, the game plan doesn't need to change.