The Blues hockey staff must define what, exactly, it has with Alex Pietrangelo. He seemed ready to become a perennial Norris Trophy candidate back in 2011-12, when he produced 51 points with a plus-16 rating. He made the game look so easy at both ends of the ice. He appeared ready to do even greater things. But Pietrangelo was merely good last season, scoring 24 points with an even rating in 47 games. He didn’t have a comfortable defense partner until rangy, smooth-skating Jay Bouwmeester arrived to settle things down. Like other key Blues, Pietrangelo failed to elevate his team during the first round of the Stanley Cup playoffs. The Blues have high hopes for the Pietrangelo/Bouwmeester tandem next season. Still, just who is Pietrangelo? What is he, in hockey terms? His restricted free agency is forcing the Blues to answer those questions. If he still has more to prove, the Blues could try to sign him to a shorter-term deal. Pietrangelo could favor that, too, believing he would drive his value up to the maximum level before committing for the long haul. If the Blues believe Alex is a true franchise cornerstone right now, then the team will want to lock him in through his athletic prime. That would require offering a contract that far exceeds anything the team has done before. As Blues general manager Doug Armstrong told Post-Dispatch reporter Jeremy Rutherford, the team isn’t worried about Pietrangelo drawing ridiculous offer sheets this summer. The new collective bargaining agreement lowered the salary cap for 2013-14 and placed some common sense restrictions on how free agent offer sheets can be structured. Spendthifts like Philadelphia Flyers general manager Paul Holmgren can no longer make ludicrous 14-year, $110 million offers like the one he made Shea Weber last summer.