Center Alex Mack is one-and-done with the 49ers, meaning Trey Lance will be fielding snaps from someone else in 2022 and beyond. Mack, after suspicions intensified in recent months, is retiring from a 13-year NFL career out of Cal, according to national reporter Mike Silver. In another 49ers retirement, they are signing running back Frank Gore to a ceremonial one-day contract. Also, top draft Drake Jackson signed his $5.8 million deal that includes $3 million guaranteed, ESPN reported. While Mack steered clear of the 49ers’ offseason program the past six weeks, coach Kyle Shanahan and general …
