Richard Sherman of the 49ers at Decibel event in San Francisco Source: Chris Conroy

Richard Sherman has a complicated relationship with the San Francisco Bay Area. He attended Stanford and helped lead the Cardinal football team to its best record ever in 2010. But three years later, playing against the San Francisco 49ers, Sherman made the key defensive play at the end of the conference championship game to preserve the win for his Seattle Seahawks, sending them to the Super Bowl. The 49ers coach at the time was Jim Harbaugh, who coached Sherman at Stanford. Now Sherman is back, starting the second year of a three-year contract with the 49ers, who entered training camp late last month with modest expectations coming off a miserable four-win season. At age 31, the four-time all star is gearing up to act as mentor to his younger teammates. But he's also preparing for what comes after the NFL. In San Francisco, that means investing in tech, often exchanging his time, brand recognition and advisory work for equity in start-ups. "Just going to Stanford and being in Silicon Valley for so long, my eyes were open to the tech community at a really young age," Sherman said in a recent interview at a start-up event in downtown San Francisco. "I've always been conscious of life after football and I needed to have a role in this industry that a lot of my friends have lived in for the past 10 years."

Richard Sherman on the field for the San Francisco 49ers. Roy K. Miller | Icon Sportswire via Getty Images

Sherman, who hails from Compton, California, just south of Los Angeles, is by no means the first Bay Area star athlete to delve into the local star-up scene. Basketball stars Andre Iguodala, Stephen Curry and Kevin Durant all built up portfolios in their time with the Golden State Warriors. But Durant just left for Brooklyn in free agency and Igoudala was traded to Memphis, so there's room for Sherman to fill some of the void. The cornerback has been at it for a while, dabbling in cryptocurrencies, e-commerce and concussion-prevention technology before his return to the area. He invested in electric carmaker Tesla years ago at about $35 a share, according to his recollection, and sold at $85 to $90 (it's now over $230). And he's already experienced some start-up failure, serving as a brand ambassador for sports jersey rental provider Rep the Squad, which shut down last year. Now he's taking another approach to the market, investing in Decibel, a new venture fund whose principal backer is Cisco. Jon Sakoda, the founder of Decibel, met Sherman through The Players Tribune, an online media company started by retired baseball star Derek Jeter to give athletes a place to write personal stories for their fans. Sakoda invested in the publication while at his previous firm, New Enterprise Associates.

Getting into software

As an investor in Decibel, Sherman is looking for ways to both help the fund and its portfolio companies. At last month's dinner in San Francisco, Sherman spoke to executives from some of the companies in an intimate setting, discussing how he approaches investments, how he prepares for big games and how data is becoming an increasingly important part of the sport. He also took a few minutes to break down the tape of his key play in the NFC Championship game and how he was able to knock away Colin Kaepernick's end zone pass so that his teammate, Malcolm Smith, could intercept it. "That little stutter right there was pointless," Sherman said, referring to wide receiver Michael Crabtree's move at the beginning of the play. "It was subtle to you guys but it was probably what lost him this play."

One of the companies in attendance was Blameless, which develops software that helps customers quickly find any glitches that pop up in their applications and determine the root of the issue. The start-up just emerged from stealth mode in March, but co-founders Ashar Rizqi and Lyon Wong have had several interactions with Sherman, including a visit they made to Seattle early this year. While they haven't discussed any formal involvement with Sherman, Wong said they've chatted in detail about the similarities in how companies and football teams use data to address problems. The idea behind Blameless is that customers create incident reports, without assigning blame, so they learn from mistakes and avoid making them in the future. Sherman sees his defensive squad in much the same way. "He specifically said the Blameless post-mortems are something he sees value in," Wong said. "Allowing him to read and predict the play before it happens — that can only be done through a lot of learning. We were chatting about how that's similar to what enterprises need to do to predict what will happen." Sherman said he's taken a particular interest in software after seeing how it's infiltrated every industry, whether it's Tesla, which he continues to follow, or the way NFL teams are using data from sensors in their player analysis. Sherman sounds like a Silicon Valley veteran when he says "just about every company now is a software company."

'I bang my head for a living'

Sherman is most outspoken when it comes to player safety, where he has two investments related to the concussion epidemic. The NFL said in January that players experienced 214 concussions last season, a 24% decline from the prior year, likely due to rules changes limiting helmet contact. But even with the decline, football remains a violent sport, and that's not changing. "I tell my friends all the time, I feel like the black sheep," said Sherman, who has two young kids. Among his college friends, "we've got doctors, we have lawyers and I bang my head for a living," he said. One of Sherman's investments is in Vicis, a Seattle-based company that makes football helmets designed to reduce the severity of head impacts. The company told CNBC last year that players from 28 of the 32 NFL teams wear its helmet.