(CNN) Former Housing and Urban Development Secretary Julián Castro has ramped up his outreach to possible donors and campaign staff since last week's midterm elections, CNN has learned, as he weighs what he has described as a "likely" run against President Donald Trump in 2020.

On Monday, Castro, the former mayor of San Antonio, held a meeting with roughly 20 possible donors in his hometown to discuss a potential presidential campaign, a source familiar with Castro's activity said. The donors were mostly Texas based, and many were longtime Castro contacts. His twin brother, Rep. Joaquin Castro, D-Texas, also attended the fundraiser, which was first reported by Politico.

Castro's recent outreach has also included meetings and phone calls with prospective staff for a possible presidential campaign, including potential staff in the early nominating state of Iowa, the source said.

Within the last week, he has also engaged in conversations with lawyers about the "mechanics of launching a possible 2020 presidential campaign," the source added.

On Wednesday, Castro will hold a fundraiser for his political action committee, Opportunity First, in San Diego, where he's also set to appear before San Diego's Regional Chamber of Commerce.

Over the past few months, Castro has openly talked about his interest in a presidential run, recently telling Rolling Stone , "I'm likely to do it."

"I have a strong vision for the country. I believe that our country's going in the wrong direction and that it needs new leadership. I'll make a final decision after November, but I'm inclined to do it," Castro told Rolling Stone last month.

Should he choose to run, Castro would potentially be one of the only Latino candidates to enter what's expected to be a crowded Democratic primary field which has already seen formal announcements from two candidates -- Rep. John Delaney of Maryland and Richard Ojeda, a former Democratic congressional candidate who lost his 2018 bid in West Virginia.

Within the past week, at least five other possible candidates -- New Jersey Sen. Cory Booker, California Sen. Kamala Harris, Vermont Sen. Bernie Sanders, billionaire activist Tom Steyer, and Massachusetts Sen. Elizabeth Warren -- were in talks with potential staff and consultants, said several Democratic sources interviewing for those roles themselves or who have friends who are doing so.

Castro could also find himself facing off against several other Obama administration alumni -- like former Vice President Joe Biden and former Attorney General Eric Holder -- as well as fellow Texan Beto O'Rourke, whose narrow loss against Sen. Ted Cruz has sparked speculation he could run for president in 2020.

"It's going to be cathartic for the party to go through a process where everybody gets to show what they've got. Where you have debates with over a dozen people and every wing of the party is represented," Castro told Rolling Stone last month.

He added "We need to go through that to get over 2016, and we're going to come out of the 2020 primary, I'm convinced, in a much stronger position. The nominee will be stronger for it and be better prepared to win in November of 2020. I'm hopeful, and I think realistically hopeful, about what this very contested, long, drawn-out process is going to mean. Most of the time a party wants to avoid that kind of process, but in this case, that's our salvation."

Throughout the midterms, Castro, who recently released his memoir "An Unlikely Journey," crisscrossed the country campaigning for candidates he endorsed through his Opportunity First PAC. He endorsed 89 candidates in the midterms.

He made trips to several early nominating states, like Iowa, New Hampshire, South Carolina and Nevada. He also campaigned for candidates in Arizona, Texas, and Florida, where he was an early endorser of Andrew Gillum's gubernatorial campaign in 2017.