Scott Brown will not run for the U.S. Senate seat vacated by John Kerry, the former senator told the Herald first today.

“U r the first to know I am not running,” Brown texted the Herald.

Brown’s decision follows yesterday’s announcement by fellow Republican Charlie Baker that he won’t run for the seat either. Baker did urge former Gov. William Weld, who just moved back to Massachusetts, to run if Brown doesn’t.

This leaves Democrats U.S. Rep. Stephen Lynch and rival U.S. Rep. Edward Markey as the only two declared candidates for the office.

Brown said in a statement this afternoon that being in the Senate was “the greatest privilege” of his life — after the marriage to his wife and the birth of his two daughters — but he’s not ready for a third Senate campaign “in less than four years.”

“Over these past few weeks I have given serious thought about the possibility of running again, as events have created another vacancy requiring another special election. I have received a lot of encouragement from friends and supporters to become a candidate, and my competitive instincts were leading in the same direction,” Brown wrote.

“Even so, I was not at all certain that a third Senate campaign in less than four years, and the prospect of returning to a Congress even more partisan than the one I left, was really the best way for me to continue in public service at this time. And I know it’s not the only way for me to advance the ideals and causes that matter most to me,” he added.

“That is why I am announcing today that I will not be a candidate for the United States Senate in the upcoming special election,” his statement ends.

The primary is April 30 and the special election June 25.

This week Gov. Deval Patrick named his former chief of staff William “Mo” Cowan as the state’s interim senator until his replacement is elected.

Joe Battenfeld contributed to this report.