Alamolhoda was speaking to the semiofficial Fars news agency, which is said to be affiliated with the Revolutionary Guards. He said that "unjust" accusations shouldn't be made against the two.
"We saw that on Student Day the picture of the imam [a reference to Ayatollah Ruhollah Khomeini, the founder of the Islamic republic] was burned, yet neither Musavi nor Karrubi were capable of burning the imam's picture, or even recommending others to do so," Alamolhoda said.
The hard-line cleric didn't directly blame Musavi and Karrubi for the postelection demonstrations that pushed the Islamic republic into serious crisis. He only said that through their stances, the two men paved the way for "foreign elements" to create unrest.
"The sedition" is the term Iranian leaders have used to refer to the opposition Green Movement that emerged following the disputed 2009 reelection of Iranian President Mahmud Ahmadinejad. Officials have repeatedly referred to Musavi and Karrubi as the leaders of the so-called sedition and accused them of being behind the postelection unrest.
Alamolhoda himself has been quoted as saying that Musavi and Karrubi should either repent or be charged as "enemies of God," which carries the death sentence. He has also famously called opposition members "a bunch of calves and lambs."
His change of tone comes just a day after a senior conservative politician, Habibollah Asgar Oladi, the secretary-general of the Islamic Coalition Party, said that the Islamic republic should not give up easily on Musavi and Karrubi.
Asgar Oladi said on December 27 that he didn't believe that the two men had ever had "seditious" intentions.
Musavi and Karrubi, both losing candidates in the 2009 vote, have accused officials of massive fraud in that election and condemned postelection human rights abuses.
Musavi, a former prime minister, and Karrubi, a former parliament speaker, were put under house arrest in 2011 after their call for a demonstration in support of the uprisings in Tunisia and Egypt attracted a significant number of protesters.
The reason for the change of tone regarding the two opposition figures is not clear. According to relatives who have managed to meet with Musavi and Karrubi, their stances remain unchanged.
However, the new milder tone could signal an effort by the Iranian establishment to reach out to reformists and opposition members ahead of the 2013 presidential election and encourage them to participate.
It could also be a sign of new behind-the-scenes debates about the fate of Musavi and Karrubi.
Last week, Iran's police chief, Esmail Ahmadi Moghadam, appeared to confirm that the two men had been put under house arrest on the orders of Supreme Leader Ayatollah Ali Khamenei.
In an interview with the hard-line "Kayhan" daily, Ahmadi Moghadam said that during the 2009 postelection unrest, security officials had presented Khamenei with a list of 40 individuals who they believed had played a role in the protests.
He added that Khamenei had opposed the arrest of several of them while taking responsibility for their fate.