Senate Majority Leader Mitch McConnell is delaying the vote on Obamacare repeal while Senator John McCain recovers from a surgical procedure.

McCain underwent surgery on Friday to remove a blood clot from above his eye. He is not expected back in his Washington office next week.

McConnell had no choice but to seek a delay because without McCain's vote, it is likely the bill would not receive the 50 votes necessary for passage.

The Hill:

"Elaine and I, along with the entire Senate family, wish John the very best and wish him a speedy recovery," McConnell said in a statement that referred to his wife, Transportation Secretary Elaine Chao.

"While John is recovering, the Senate will continue our work on legislative items and nominations and will defer consideration of the Better Care Act."

McCain underwent a procedure to remove a blood clot from his eye on Friday, according to statements from his office and the Mayo Clinic. He is recovering at home in Arizona.

Sens. Rand Paul (R-Ky.) and Susan Collins (R-Maine) have already said they would oppose a procedural vote to advance to the new Senate GOP healthcare legislation, which was unveiled this past week. With all Democrats voting no, that would leave Republicans with just 49 votes, given McCain's absence.

The further delay in the schedule is a problem for McConnell, as opponents of the legislation could use the extra time to pressure wavering GOP centrists to vote against it.

The healthcare bill was already on rocky ground even with McCain, as many speculated whether McConnell could pull together 50 votes.

This is the second time McConnell has had to put off Senate consideration of ObamaCare repeal.

Work was also postponed in late June after it became clear McConnell lacked the support to carry the bill through the Senate.

That prompted a rewriting of the legislation, which won over Sen. Ted Cruz (R-Texas), a key conservative.

A number of centrist Republicans, however, remain on the fence as McConnell awaits a Congressional Budget Office analysis and score of the legislation, which is expected on Monday.

How much trouble is the Obamacare repeal bill in if McConnell has to depend on the vote of John McCain for passage?

Although McCain has been an historically unreliable vote on some issues, he has been fairly consistent in voting to repeal and replace Obamacare. But McCain isn't the problem in this case. McConnell is under increasing pressure to ditch the amendments offered by Senator Ted Cruz that throw out many of the "mandated" coverages that insurance companies are forced to offer with every Obamacare policy. Cruz's additions to the bill has garnered widespread conservative support in the Senate, but has left many moderates cold.

But the GOP ace in the hole is the president and his ability to sway fence sitters to support his agenda. Perhaps the extra time before the vote will be put to good use as the White House develops a full court press lobbying campaign to convince the moderates that a "no" vote will deep six the rest of his agenda, including tax reform. 

Trump must convince these Senators that they must all hang together or they will hang separately.