Citigroup lowered its 2012 EPS estimate for Hospira (NYSE:HSP) and maintained its sell rating and $54 price target on the stock.The bank sees 2011 EPS of $4.04, vs. consensus estimates of $3.99 per share, and now sees 2012 EPS of $4.40, down from $4.44 per share, vs. consensus estimates of $4.48 per share.Hospira has a potential upside of 15.6% based on a current price of $54.37 and an average consensus analyst price target of $62.83.