49ers deliver unfortunate injury news on Connor Colby, Jordan Watkins, Spencer Burford

San Francisco 49ers quarterback Brock Purdy (toe) is officially listed as "questionable" for Sunday's game against the Arizona Cardinals. However, head coach Kyle Shanahan admitted it's unlikely Purdy will be healthy enough to start, leaving Mac Jones as the probable Week 3 starter for the second straight game.

Purdy's status wasn't the only update Shanahan provided. The coach revealed that rookie offensive lineman Connor Colby is also "questionable" after suffering a groin injury during Thursday's practice. Colby was expected to step in at left guard with Ben Bartch on injured reserve.

So who's next in line if Colby can't go?

"It'll be a surprise for everyone," Shanahan said. "But it could be Drew Moss, it could be [Nick] Zakelj. It could have been Spencer [Burford], but he went down. Some more guys I could probably mention, but most likely one of those two."

Wide receiver Jauan Jennings is "questionable" after missing the entire week of practice due to ankle and shoulder issues. The depth concern at receiver worsened when rookie wideout Jordan Watkins was ruled out with a calf injury sustained on Thursday. Shanahan noted that Watkins could miss multiple weeks.

"You never know with calves, but guess around three to four," Shanahan explained, adding that injured reserve is a possibility.

The 49ers also lack clarity on offensive lineman Spencer Burford, who suffered a knee injury in Week 2. He has already been ruled out for this weekend.

"I just know it didn't go as well as we wanted it to this week, which is why he's out," Shanahan said. "And we'll see, probably after this weekend, whether we've gotta make a longer-term decision with it."

Shanahan confirmed that surgery could be required, which would also make Burford a strong candidate for injured reserve.