Sen. Bob Corker (R-Tenn.) said on Friday that he will oppose the GOP tax plan, making him the only GOP senator currently expected to vote no.

Corker has long said he could vote against the bill if it hiked the deficit, and he reconfirmed to those concerns in his statement.

"This is yet another tough vote. I am disappointed. I wanted to get to yes. But at the end of the day, I am not able to cast aside my fiscal concerns and vote for legislation that I believe, based on the information I currently have, could deepen the debt burden on future generations," Corker said in a statement.

He added that while he supports parts of the Senate legislation and believes it could be made more "fiscally sound ... it is clear the caucus is in a different place."

Corker's decision won't impact the fate of the Senate Republican legislation. Leadership secured 50 "yes" votes earlier Friday, and GOP Sen. Susan Collins (R-Maine), who had been the only other holdout, said she would support the bill.

He also left the door open to ultimately supporting the final compromise between House and Senate negotiators.

"As I shared with President Trump when I called him a short time ago, I will take a close look at the product developed in conference before making a decision on the final legislation," he said.

Corker's decision to vote against the legislation comes after days of closed-door meetings with leadership and other key senators to try to reach a deal that would guarantee the tax legislation didn't increase the deficit.

Corker and Sen. James Lankford (R-Okla.) initially tried to get a trigger included that would spark automatic tax increases if the bill didn't create the economic growth that Republicans are hoping for.

Corker, who is retiring after 2018, told reporters earlier this week that he had an agreement "in principle" with Sen. Pat Toomey (R-Pa.)

But the proposal ran into trouble with the parliamentarian, who was spotted on the Senate floor speaking to roughly two dozen senators during a dramatic showdown on Thursday night.

Senators say the automatic "trigger" didn't pass muster with the Byrd rules, which govern what can be included under the process Republicans are using to pass their legislation with a simple majority.

Instead, leadership offered to include automatic tax increases in the legislation. But that proposal got swift and immediate backlash from other Republicans, including Sen. Ted Cruz (R-Texas).

"It would have been counterproductive to the central objective of this legislation, which is bringing back jobs and economic growth," said Cruz. "And after extended discussion with a number of senators a consensus emerged that we shouldn't be raising taxes."

Republicans said after a closed-door caucus meeting on Friday that they were dropping the tax hikes and leadership appeared ready to move the legislation with or without Corker's support.

"Senator Corker gave a few remarks today at our conference and I thought was exceedingly gracious. He obviously has a point of view, which we all respect. ... But we just think this is a much stronger pro-growth tax-reform plan," said Sen. John Cornyn (R-Texas).