Thomas graduated from Stanford last year, and signed with the New Orleans Saints as an undrafted free agent. The Saints waived him, and he bounced around a couple teams after that, signing with the Atlanta Falcons practice squad last September. He signed with the Packers in January, and was released a week ago Monday.
While Trent Baalke and company have not drafted a Stanford player since 2003 (Kwame Harris), they have provided plenty of opportunities through undrafted free agency and minicamp tryouts. The team already signed Shayne Skov to a UDFA deal this offseason, and of course added Jonathan Martin via trade. The most notable recent Stanford man would have to be Michael Thomas. He spent his time on the practice squad before signing with the Miami Dolphins 53-man roster.
The 49ers rookie minicamp takes place this coming weekend, and will feature a mix of draft picks, UDFAs, tryout players, and some second year players on the current roster. Marcus Lattimore, Luke Marquardt, Carter Bykowski, Chuck Jacobs, and Mike Purcell can all take part. Tank Carradine cannot take part because he was on the 53-man roster for five games last season. He does not accrue a season toward free agency (requires 6 games), but he gets a credited season (requires 3 games), thus the distinction on rookie minicamp. He also accrued a season toward free agency because he was on the 53-man roster and IR for 6+ games.
Speaking of minicamp, Matt Barrows had an article on some return work Bruce Ellington has been handling in football school thus far. He seems to be the front-runner among the rookies to get a shot at return work.