Each team is allowed 11 men on the field at the time the ball is snapped. Unlimited substitutions are permitted throughout NFL games but players may only enter the field when the previous play has been whistled dead. Players leaving the field must be off the pitch by the time the new play has begun.

replacing one player with another. This may occur between periods, after a goal is scored, or to replace an ejected player.

Traditionally the most expensive errors to correct. Consists of those characters that a recognition engine is convinced it got right but that are in fact wrong. High levels of 'accuracy' reported by an OCR engine can mean that there are many substitutions. The alternative is to set tolerances very high -- then the engine will often report low accuracy -- but there may be many correctly interpreted characters which are labelled wrong.

the same or similar products to the product you are selling to customers.

Please see our substitutions page.