WEEI.com has learned the Patriots and second-round draft pick Sebastian Vollmer have preliminarily agreed on a contract. Vollmer, an offensive lineman out of the University of Houston, was the 58th overall pick in the 2009 draft. If the deal is signed, the 24-year-old Vollmer would be the fourth of New England’s 12 draft picks to agree to a contract — fellow second-round pick Darius Butler, fourth-round selection Rich Ohrnberger and sixth-round pick Myron Pryor are all reportedly in the fold.