NEW YORK -- Option traders are betting that Transocean (RIG - Get Report) will rally after it reports earnings next week. 

OptionMonster's Heat Seeker system detected the purchase of 23,863 March 22 calls in a single print for 14 cents on Friday. Those contracts reached 28,800 by the end of the session, with premiums rising to 23 cents. Open interest in the strike was just 2,337 options before the trades occurred, showing that this is fresh buying. 

The bullish activity followed heavy volume in the March 21 calls cited by OptionMonster co-founder Jon "DRJ" Najarian on Feb. 9. Transocean is scheduled to announce quarterly results after the market closes on Feb. 25. 

These long calls lock in the price where the stock can be purchased through mid-March no matter how far it might climb. They could be sold earlier at a profit if premiums rise with a rally before then, providing potentially significant leverage, but the contracts will expire worthless if shares stall or pull back. 

RIG rose 2.25% to $19.05 on Friday. The offshore driller plummeted after trading above $45 last summer but has gained 23%t in the last month.

Total volume in the name on Friday was 64% higher than its daily average. Overall calls outpaced puts by more than 2.5 to 1.

-- Written by Mike Yamamoto of  OptionMonster

Najarian owns RIG calls; Yamamoto has no positions in the name.