Wall Street uneasy after Greece deal; Yellen eyed By: CNBC.com News February 23, 2015 at 06:01 AM EST U.S. stock index futures signaled a lower open on Monday as uncertainty surrounded Greece's deal with its euro zone creditors to extend its bailout. Read More >> Related Stocks: Agrium, Inc. Express Scripts Holding Oneok Inc Sentinelone Inc Cl A Tenet Healthcare