As John points out, Chuck Schumer's been on a tear lately, voicing strong support for a public option:

"This is where we are going to end up," he said of a health care overhaul that included a public plan. "And I think, it would be much better for the Senate Finance Committee if we did it in the committee... I think the Senate HELP committee compromised already, because you have a lot of members on the HELP committee who would've liked [the public option] to be much closer to Medicare. The idea seems to be catching everybody's imagination, and sense of fairness. And the only holdouts are sort of ideologues on the Republican side of this saying no government involvement whatsoever."

But he's not freelancing. Schumer and Reid are close partners in leadership -  their 'loud cop/quiet cop' division of labor is strategic:

With Obama very much the public face of the Democratic Party, Reid allows his much more loquacious top lieutenants, Richard J. Durbin of Illinois and Charles E. Schumer of New York, to take more public responsibility for party message delivery and partisan jousting in the Senate while he concentrates on the behind-the-scenes role of wooing colleagues -- the job he excelled at in his six years as whip before becoming floor leader.

Whipping Senators isn't easy - they can't be pushed around like Reps in the House. But the division of labor strategy suits Reid and Schumer well. Schumer doesn't always speak for Senate leadership, but I'd bet he does on health care.