Sen. Bernie Sanders (I-VT) may be building momentum once again ahead of the crucial June 7 primary in California, where 475 prized pledged delegates are at stake.

On Monday, Sanders was able to draw 15,000 supporters to a rally in Sacramento and attacked rival Hillary Clinton for her ties to Wall Street and for supporting the War in Iraq.

Yet Sanders has not yet committed to buying television ad time in the Golden State.

On Monday, Sanders told the Sacramento Bee on Monday that his campaign “may end up doing” TV, indicating it could be a last-minute ad buy instead of a comprehensive campaign over the next few weeks. Radio ads and leaflets are far less effective than TV ads in the vast state.

“You know, we’re in reasonably good financial shape, but TV is so expensive here in California, you could just spend millions of dollars in a few days,” Sanders told the Bee. In the interim, Sanders praised the efforts of his vast team of on-the-ground volunteers and laid plans to hold rallies for “hundreds of thousands” of people in California over the next few weeks.

On Monday, Sanders’s reception at Bonny Field, where actor Danny Glover introduced him, was indicative of that. “It turns out that a lot has changed in a year,” Sanders told the bustling crowd. “The corporate establishment is getting nervous. The political establishment is getting nervous. When they see 15,000 people coming out in Sacramento, they get very nervous. And they should be getting nervous, because real change is coming.”

RNs in Sacramento are feeling the Bern! #feeltheBern pic.twitter.com/IcZzzPy6ED — Ginger CNA NNOC (@GDFCNA_NNOC) May 10, 2016

A lot has changed for Sanders indeed. Just one year ago, Clinton held a 66% to 9% advantage over Sanders in California. However, Clinton’s lead over Sanders has diminished significantly in the state

And his momentum appears to be far from over. DiCamillo told the Sacramento Bee, “It does appear to me that Sanders is getting stronger over time. We’ll see where the momentum is as we approach June.”

At his rally, Clinton’s name was reportedly booed, although some present said they would still vote for her if she became the nominee just to stop Trump.

Sanders will be traveling to the San Joaquin Delta this week, and will appear in Stockton on Tuesday. Both are areas plagued by drought issues.

Beyond the California primary, Sanders has predicted a contested convention in July. Sanders said he is also “prepared to mobilize our delegates to force as many votes as necessary to amend the platform and rules on the floor of the convention.”

Some Sanders supporters are promising to “occupy” the Democratic National Convention in Philadelphia.

Follow Adelle Nazarian on Twitter @AdelleNaz