The real "gap" to be bridged in the debate over healthcare reform legislation isn't between centrist and liberal Democrats in the House -- it will be between House and Senate's different bills, one key Blue Dog Democrat said Tuesday.

Rep. Jim Cooper (D-Tenn.), a centrist Democrat and healthcare expert, said during an interview on CNN that, because of Senate rules, the upper chamber's bill will likely be more bipartisan and centrist than the House bill.

"We can...get a bipartisan bill. They're working on that in the Senate," Cooper said. "But unfortunately, the House has been reluctant to take that approach."

"The Senate will be the real gap here," the Tennessee Democrat continued. "They have to get 60 votes to pass anything. And that requires some form of bipartisanship."

Cooper said that after Blue Dogs' negotiations with leaders on the House Energy and Commerce committee, there were no "bright lines" proving barriers to compromises on a health bill in the House.