Stopping Clock with QB Sack in NFL

[OnlyRefFB]

Snake-eyes - You're on the money. Markbreit said the same thing in his column.

However, this does not apply in the last 2 minutes of either half.

[Question]
"Being a high school official, I've never understood the rules surrounding the clock being stopped when the QB is sacked. What is the rationale for stopping the clock in this situation, and what conditions are needed for the clock to actually be stopped? --Mark Dexter, Plainfield, Conn.

[Markbreit's Response]
This rule only exists in the National Football League. The reason is to allow the deep receivers time to return at or near the line of scrimmage before the clock starts again. Several years ago, this rule was modified. Now the clock is not stopped on sacks during the last two minutes of each half."

http://chicagosports.chicagotribune.com/sports/football/bears/askthereferee/cs-051228askjerrymarkbreit,1,1174018.story?coll=cs-bears-asktheref-headlines