It's only the second week of the season, but the 49ers already are down to starting their third-string right guard. At least that's the likely scenario for Sunday's game against the visiting Lions after starter Mike Person (foot) and his backup, Joshua Garnett (toe), missed their second straight practice Thursday. If they can't play, head coach Kyle Shanahan said the 49ers will turn to Najee Toran, an undrafted rookie from UCLA who was elevated from the practice squad Monday. "I'm expecting (Toran) to be our guy here Sunday unless we can have a miraculous recovery by some of the other guys," Shanahan said on KNBR. Toran, an honorable-mention All-Pac 12 choice in 2017, made 13 of his 24 college starts last year.