Hundley went 0-for-3 in Friday night's 4-0 loss to the Padres.
The plan was for Hundley to be activated at some point during the current road trip; Wolters' injury on a foul tip accelerated the return. Hundley, hitting .273 with two home runs and seven RBIs in 13 games this season, returns knowing that oblique injuries have a high recurrence rate.
"It can recur for sure if you don't stay on top of it, but our training staff does a really good job," said Hundley, 32, who played for the Padres in 2008-14. "I've been impressed the year and a half they've been over here how proactive they are."
Wolters, 23, who is hitting .217 and ranking high in several advanced catching metrics, was injured in the top of the fifth inning of Thursday night's 11-4 loss to the Reds at Coors Field. He finished the frame.
"I just came to the dugout and my stomach was kind of hurting, and I felt a little sick, queasy," Wolters said. Nausea can be a concussion symptom.
Wolters didn't participate in any pregame activities Friday, but expects to be brought along over the next several days. Hundley missed time earlier this season on the concussion DL.
"The more you hear about the dangers of concussions, my message is to be honest with yourself," Hundley said. "There are some things you can play through, some things you can't play through, and that's one of them. I had some concussion stuff in 2012 that I wasn't honest about, and it didn't turn out very well.
"This time around I was honest about how I felt. I didn't feel bad about it, wasn't ashamed. I don't think you're ashamed but you think you can play through anything."
• Pirates pitcher Ryan Vogelsong, struck in the face by a 92-mph fastball from Rockies pitcher Jordan Lyles, underwent surgery Thursday to repair multiple facial fractures and is resting comfortably at home, according to a statement from the Pirates. Lyles is pitching at Albuquerque.
• Rockies outfielder Carlos Gonzalez and the Red Sox's David Ortiz entered Friday's play tied for the most home runs (46) in the Majors in the last 365 days, from last June 3 to Friday. Gonzalez did not start Friday, partly to rest during a 27-day stretch without an off-day, partly because the Rockies were facing Padres left-hander Drew Pomeranz. Going into Friday, Gonzalez's .455 average since May 23 was the highest in the Majors. He hit safely in 10 of the 11 games, and homered in six of the last eight contests.