President Donald Trump said he won’t rule out a presidential pardon for his former campaign manager and convicted felon Paul Manafort, a witness in Special Counsel Robert Mueller’s investigation into possible collusion with Russia in the 2016 election.

The possibility of a pardon is “not off the table,” Trump said in an interview with the New York Post published Wednesday, adding that it hasn’t been specifically discussed. “Why would I take it off the table?”

Mueller said Monday that a cooperation deal between prosecutors and Manafort was void after he repeatedly lied to authorities. The rupture could have dire consequences for the 69-year-old Manafort, who has sought to avoid spending the rest of his life in prison after being convicted of bank and tax fraud.

Trump and his lawyers have previously declined to comment on whether he’d consider pardoning Manafort. Signaling a pardon is in the offing could be seen as an attempt to obstruct justice or tamper with a witness if it’s intended as a quid pro quo, in exchange for Manafort giving testimony favorable to Trump.

Trump lawyer Rudy Giuliani said he has kept in touch with Manafort’s lawyer since the plea agreement was reached, but the extent of their communication is unclear.

Trump has revived his attacks on Mueller, tweeting Tuesday that the special counsel is “ruining lives” of witnesses who refuse to lie. Trump has previously called Manafort a “good man” and claimed Mueller treated him unfairly.