According to Mike Klis of 9News, the Broncos figure to receive trade inquiries about QB Trevor Siemian if they end up signing Tony Romo at some point this offseason.
Klis mentions that the 49ers figure to be one team worth keeping an eye on in regards to a potential trade involving Siemian, as new HC Kyle Shanahan reportedly mentioned during his interview with the Broncos that he was impressed with Siemian last year.
As of now, the 49ers do not have a single quarterback under contract, so even if they intend to draft someone this April, they would still need some more options at the position.