The referee's assessor at the game claimed that Torpey had been involved in an incident with Warren Goodhind, after the Cambridge defender had been red-carded for a dangerous tackle on the tall striker.
But the FA have cleared Torpey after reviewing video of the incident and taking into consideration a statement from Torpey.
Iron boss Brian Laws said: "We're really pleased.
"Steve Torpey is a very important player for us, and to lose him for three games would have been a massive blow for us."
Torpey, who scored within 40 seconds against Swansea on Saturday, is free to continue his fruitful partnership with Paul Hayes against Rushden and Diamonds on Saturday.