Sen. John McCain (R-AZ) returned to Arizona for rehabilitation as he undergoes cancer treatment and will not return to Washington, D.C. until January, the senator’s office announced Sunday evening.

McCain will not be present for the vote on the Republican tax cut bill, though the GOP appears to have enough support for the legislation to pass the measure without McCain’s vote.

President Donald Trump told reporters Sunday evening that he spoke with McCain’s wife and that he understands McCain would return to Washington, D.C. if Republicans need his vote.

“I wished her well. I wish John well. They’ve headed back. But I understand he’ll come if we ever needed his vote, which hopefully we won’t. But the word is John will come back if we need his vote,” Trump said. “It’s too bad. He’s going through very tough time, there’s no question about it. But he will come back if we need his vote.”

The senator, who was diagnosed with cancer earlier this year, was treated for a viral infection at Walter Reed Medical Center in Washington, D.C. last week, his doctor said in a statement released by McCain’s office. He then returned to Arizona to recover, his office said.

“Senator McCain has returned to Arizona and will undergo physical therapy and rehabilitation at Mayo Clinic. He is grateful for the excellent care he continues to receive, and appreciates the outpouring of support from people all over the country. He looks forward to returning to Washington in January,” McCain’s office said in the statement.