BOSTON (CBS) – Massachusetts Congressman Joe Kennedy III said Monday he is indeed considering a run for Senate, confirming speculation that he has plans to take on Sen. Ed Markey in 2020.

“Over the past few weeks I’ve begun to consider a run for the U.S. Senate,” Kennedy wrote in a Facebook post. “This isn’t a decision I’m approaching lightly and — to be completely candid — I wasn’t expecting to share my thoughts so soon.”

Keller @ Large: Kennedy Thinks He Can Beat Markey

Kennedy, a father of two young children, said family will be a major consideration as he weighs getting into the Democratic primary.

“I haven’t reached a decision yet — that’s the truth,” he wrote. “I’m thinking about what I have to offer Massachusetts voters, what is most important in this political moment, and what kind of party Democrats need to be building for the future.”

Just last week, Markey released a video of Sen. Elizabeth Warren endorsing his re-election bid. Markey was a longtime Congressman in the state before winning the Senate seat once held by John Kerry in 2013.

“I am running for re-election, I am criss-crossing the state and I am fighting for the people of Massachusetts,” Markey told reporters.

“I’m going to continue to fight for the things the people of Massachusetts want me to stand up for. That’s all I’ve done from the day I’ve been given the honor of representing the state and that’s what I’m going to continue to do,” he added.

A spokeswoman previously said Kennedy is focused on running for re-election to represent the state’s fourth Congressional district. But Kennedy said he doesn’t believe he “should wait my turn” and has ideas about how to fix the system.

“I plan to spend the next couple weeks talking to as many of you as I can, trying to figure out if this campaign is right for me and right for Massachusetts,” he said. “I’m grateful for your thoughts, encouragement and especially your patience as I weigh a big decision.”

Workers’ rights lawyer Shannon Liss-Riordan and former Walgreens executive Steve Pemberton have already announced challenges to Markey.