affect APR. When a scholarship athlete goes on a mission, you lose the 1 out of 2 possible APR points for that student for retention.
http://www.deseretnews.com/m/article/700045884
APR is only calculated based on existing scholarships. If a student-athlete played, but was not a scholarship player, then that athlete's status doesn't affect APR one way or another. That's one reason why non-FB sports (that have low scholarship numbers) aren't as badly affected by missions when you calculate APR. I think volleyball has a total of 4 scholarships. Most of the other sports are not giving out full scholarships. They're splitting the scholarships among players and giving out 1/2 scholarships and 1/4 scholarships.