Former GOP Rep. Paul Loscocco, who had been running as an Independent for lieutenant governor as the running mate of Treasurer Tim Cahill, announced suddenly Friday that he is leaving the ticket and endorsing Republican Charles Baker for governor.

The Baker campaign is planning an 11 a.m. press conference at its Boston headquarters. A Cahill campaign spokeswoman did not immediately a call seeking comment.

Loscocco’s decision to join Cahill’s ticket surprised the GOP because Loscocco had pledged his support to Baker as early as July 2009. That month, Loscocco told the News Service he was “extremely excited” Baker's candidacy and declined to rule out joining the Republican ticket in the number-two spot.

“I think it's way too early for me to speculate about who's going to be the lieutenant governor,” the Holliston Republican said. “I will be very happy to support Charlie any way I can.”

A Loscooco campaign aide sent the following excerpt from Loscocco's planned remarks:

"I ran to have a spirited debate on the issues and to advocate for new ways to create jobs, lower taxes, protect personal freedoms, and fight for the principles of Ronald Reagan who inspired me to become a Republican as a young man. The primary between the Independent ticket and Republican ticket in the hearts and minds of the voters who want a change from Governor Patrick is now over.

“Charlie Baker and Richard Tisei have prevailed over Tim Cahill and me. I cannot sit idly by as my friends and supporters cast their votes for my ticket, knowing that the best chance to defeat Governor Patrick is with Charlie Baker. I cannot and will not let my ego get in the way of doing what is right for Massachusetts. So while this is a tough decision for me today personally, it is the right decision to put the future of our state ahead of my own self-interest. Charlie Baker has the experience that can help Massachusetts head in a new direction and I'm pleased to endorse him today.

“This election is an opportunity to put Massachusetts back on track towards economic recovery. I urge voters who want new leadership on Beacon Hill to join me in voting for Charlie Baker and Richard Tisei on Election Day."