I doubt it , as I don't think he makes a decision in Iraq without consulting the US first.
What comes to my mind is a power struggle, with Maliki, trying to appear as if he is not totally in the pocket of the US. Hence we see the US distancing themselves from the turmoil in Basra, though it is quite clear they have been active all along.
Sadr, seems to have lots of support amongst the population , and has plenty of people running in a local election in Basra, they seem destined to win. The US can't lose control of this vital port city.
Iraq PM Reverses Course, Freezes Raids
In a dramatic reversal, Iraq's prime minister ordered a nationwide freeze Friday on Iraqi raids against Shiite militants, bowing to demands by anti-U.S. cleric Muqtada al-Sadr only one day after promising to expand the crackdown to Baghdad.
Prime Minister Nouri al-Maliki issued the order after al-Sadr, whose Mahdi Army militia fought government troops last week in Basra and elsewhere, hinted at retaliation if Iraqi security forces continue to arrest his followers.
A statement by al-Maliki's office, broadcast on government television, did not mention the Mahdi Army by name or give a timeframe for the freeze. It said the move was designed to give a "chance to those who repented and want to lay down their arms."
But the statement was issued less than 24 hours after al-Maliki told reporters he intended to launch security operations against Mahdi Army strongholds in Baghdad, including Sadr City, home to some 2.5 million Shiites and the militia's largest base.