Key Ukraine witness Gordon Sondland is set to testify next week. Trump allies reportedly see a 'silver lining.'

U.S. Ambassador to the European Union Gordon Sondland's testimony is back on.

Sondland, a key figure in President Trump's Ukraine scandal, was expected to testify before Congress this week, but his deposition was blocked by the State Department. At the time, Sondland's counsel said he was "profoundly disappointed." Democrats subsequently issued a subpoena for Sondland to testify on Oct. 16.

Now, Sondland's counsel has confirmed that "notwithstanding the State Department's current direction to not testify," he will "honor" the subpoena and do so, although his testimony has been rescheduled for Oct. 17. Sondland's attorney said, however, that "federal law and State Department regulations prohibit him from producing documents concerning his official responsibilities" that Congress has requested.

The way some Trump allies see it, this might not be such a bad thing, with Axios previously reporting that since the State Department blocked Sondland, "Republicans close to Trump encouraged the president to let the ambassador come before the committees," as they "believe Sondland's testimony will be helpful to their side."

"Sondland could be a silver lining," the source said. "... He donated $1 million to Trump's inaugural. He's a Trump guy."

Sondland is a key witness in the scandal sparked by Trump's call to Ukraine urging its president to investigate former Vice President Joe Biden. He is named in the recent whistleblower complaint that sparked an impeachment inquiry and in text messages released last week discusses the withholding of military aid to the country. "Are we now saying that security assistance and [White House] meeting are conditioned on investigations?" Bill Taylor, the U.S diplomat to Ukraine, asks Sondland is one exchange. Sondland replies, "Call me."