On Saturday morning, Massachusetts Rep. Joseph Kennedy III is expected to announce that he'll be running against Sen. Ed Markey.

Chuck Todd, host of "Meet the Press Daily" on MSNBC, spoke with Boston Public Radio on Thursday about the timing of Kennedy's challenge.

"I understand why [Kennedy's] doing it now," Todd said. "Kennedy sees the changing faces of the Democratic party, and I think he realizes if he waits for the next Senate opening, he might be third or fourth in line. While I think he wishes he doesn't want to have to beat Markey to get this Senate seat, I think he realized if he ever wants to be a senator, it's now or never."