NEW: Sen. Chris Van Hollen is now open to a run against Senate Minority Leader Chuck Schumer
Van Hollen has "received an outpouring of calls and is now in active listening mode," according to a person familiar w/ his thinking around leadership
"The door is not shut," the person added
Van Hollen is a leading progressive & has said he needs commitments from Schumer before agreeing to support him for another term as leader. The Maryland Democrat has also been eyeing a presidential run