One put player expressed some strong bearish convictions on United States Steel Corporation (NYSE:X - 23.36) on Thursday, with the speculator rolling his contracts down to a lower strike to bet on a continued slide in the commodity stock. Specifically, several large blocks totaling over 10,000 contracts traded near the bid price on X's January 2013 24-strike put, suggesting they were sold, while several matching blocks simultaneously changed hands near the ask price on X's January 2013 22.50-strike put -- indicating they were likely purchased. Open interest at the January 22.50 strike jumped overnight by 10,220 contracts, while the January 24 put lost a total of 8,181 contracts.

In other words, it looks as though a single speculator sold to close his 24-strike puts, and replaced them with an equal number of 22.50-strike puts -- thereby "rolling down" his bearish position on X. This strategy is typically used when a trader is feeling confident about the way his option strategy is playing out, since the lower-strike puts will only profit if X pulls back significantly over the next three weeks until front-month expiration.

X is down 1.2% at last check, backing down from a test of the $25 level. This region previously served as support, but has capped the stock's rally attempts throughout late December.