With some tech companies struggling post-IPO, Silicon Valley could start looking elsewhere for cash — namely, to Japanese billionaire Masayoshi Son, technology investor Jason Calacanis told CNBC's "Squawk Alley" on Friday.

"There's this other optionality, the Masa-IPO," Calacanis said. "In Silicon Valley now, everybody's talking about, 'Why IPO when you can just Masa-PO?' Masa's going to save all these companies and put the money in and we're good. So I feel great about it."

Son, the SoftBank CEO, has pledged to invest $100 billion in artificial intelligence, including robots and autonomous vehicles, using an unrivaled sum of money known as the Vision Fund.

SoftBank has invested in companies such as Nvidia and SoFi, both of which the Vision Fund — which is also backed by non-SoftBank investors — may also invest in.

Calacanis was an investor in Uber — a company that's considering taking money from SoftBank after a flurry of controversies earlier this year.

Uber CEO Dara Khosrowshahi said this week that while he and his board want Uber to go public, SoftBank is a long-term investor with little interest in an IPO.

"Our bringing in SoftBank as a strategic investor at the right price would be a good thing," Khosrowshahi said in an interview by New York Times columnist and CNBC anchor Andrew Ross Sorkin at The New York Times DealBook Conference.

Not everyone is as bullish as Calacanis and Khosrowshahi. Oaktree Capital's Howard Marks said the "willingness of investors to invest in a shockingly large fund for levered tech investing with a questionable structure is a further indication of an exuberant, unquestioning market."

Bill Gurley — another venture capitalist who invested in Uber — has long cautioned that a sparse IPO market and high private valuations could lead to recklessness from start-up founders and investors.

"Founders have come to believe that more money is better, and the fluidity of the recent funding environment has led many to believe that heroic fundraising is a competitive advantage. Ironically, the exact opposite is true. The very best entrepreneurs are relatively advantaged in times of scarce capital," Gurley wrote in 2016, before SoftBank's Vision Fund entered the scene. "Loose capital allows the less qualified to participate in each market."

Son has brushed off the idea that the Vision Fund is affecting start-up valuations or creating any sort of peak.

"My track record the last 18 years is 44 percent, compound every year," Son told Sorkin in a separate conference in October. "People call me high risk, high return. High return, definitely yes. But I don't know if it's high risk. If you think deep enough, if you work hard enough, if you smartly select ... I think it's not only high return but could be good."

— CNBC's Sally Shin and Leslie Picker contributed to this report.