Sen. Marco Rubio, R-Fla., will skip this month's GOP convention in Cleveland to focus on his re-election bid, a spokeswoman said Wednesday. 

Olivia Perez-Cubas said that Rubio, who unsuccessfully sought the Republican nomination for president earlier this year, had planned to attend the convention before deciding last month to seek another Senate term.

"Florida has always been a competitive state and it will be this fall," Perez-Cubas said in a statement. "Since Marco got into the race late, he will be in Florida campaigning and meeting with voters instead of going to Ohio."

Rubio would be one of many prominent Republicans who will miss the convention, at which Donald Trump is expected to officially be named the party's presidential nominee. Others include former Florida Gov. Jeb Bush, 2012 nominee Mitt Romney, 2008 nominee John McCain, Maryland Gov. Larry Hogan and New Hampshire Sen. Kelly Ayotte. 

Earlier Wednesday, one of Trump's former primary rivals, Wisconsin Gov. Scott Walker endorsed Trump in a tweet that didn't mention the real estate mogul's name.