SANTA CLARA, Calif. — Receiver Adam Thielen put his heavily-taped ankle through a pregame warmup that lasted fewer than 10 minutes at Levi's Stadium, then he rejoined his fellow Vikings receivers in catching passes from Kirk Cousins.

Thielen, who had 129 yards in the Vikings' NFC wild-card win in New Orleans, is officially active for Saturday afternoon's NFC divisional playoff game in San Francisco.He had been listed questionable after requiring stitches to seal a laceration on his ankle suffered during Wednesday's practice.

Thielen was "cleated" during the practice, a league source told the Star Tribune this week, but he has declined to discuss specifics of the injury.

The Vikings will only be shorthanded in the secondary, where cornerback Mackensie Alexander was placed on injured reserve following knee surgery. He joined cornerback Mike Hughes (neck) on IR; the second-year pro was also injured in practice. Safety Jayron Kearse was deactivated due to toe and knee injuries.

Safety Andrew Sendejo is again expected to defend the slot, but he may not get that much run against a 49ers offense that plays a lot of heavier personnel. Rookie defensive back Nate Meadors, promoted from the practice squad this weekend, will provide depth.

The 49ers are healthier after a first-round playoff bye and will return linebacker Kwon Alexander, guard Mike Person, safety Jaquiski Tartt and defensive lineman Dee Ford.

Vikings' inactives: Kearse (toe/knee), OT Oli Udoh, G Dru Samia, DT Eddie Yarbrough, DT Hercules Mata'afa, OT Aviante Collins and WR Alexander Hollins

49ers' inactives: QB C.J. Beathard, RB Jeff Wilson, WR Jordan Matthews, TE Daniel Helm, DL Kevin Givens, LB Azeez Al-Shaair and CB Dontae Johnson