Jennings focusing on health

Some expect the San Francisco 49ers offense to evolve with second-year quarterback Trey Lance at the helm. While that is probably true, it will not be by design. There won't be a drastic change to the playbook. Instead, Lance can extend plays and potentially get the football further down the field for some explosive plays. Head coach Kyle Shanahan spoke with reporters before Saturday's practice and was asked about the playbook. Is he considering changing it to take advantage of Lance's unique athleticism? "Not really at all," Shanahan responded. "I mean, you do the same stuff, and you just got a couple of more elements. When you have the threat of a running quarterback, that can change defenses. And when you see how that changes them, then you adjust to