SANTA CLARA, Calif. -- One day after San Francisco 49ers wide receiver Kendrick Bourne tested positive for COVID-19, that result has led to the NFL taking a deeper look into possible protocol violations.

While it's standard procedure for the NFL to look into all positive tests at team facilities, a league source told ESPN's Adam Schefter that the NFL is investigating whether Bourne has been wearing his protective face covering properly and frequently enough.

If Bourne is found to have not complied with protocols, the 49ers would be subject to league discipline, including a fine. That news comes on the same day the 49ers' latest group of test results revealed no positive tests for Bourne or anyone else on the roster, multiple league sources told ESPN.

Despite all of that, Bourne, as well as wideouts Brandon Aiyuk and Deebo Samuel and left tackle Trent Williams, all of whom are considered "high-risk close contacts," remains on the reserve/COVID-19 list and will not be available Thursday night against the Green Bay Packers. Players considered high-risk close contacts must remain on the reserve/COVID-19 list for at least five days and continue testing.

Given the absence of that quartet and the team's many other injuries, the Niners made a series of roster moves to restock the roster in time for Thursday night's game.

The Niners created two roster spots by placing quarterback Jimmy Garoppolo (ankle) and tight end George Kittle (foot) on injured reserve. They must miss at least the next three games, though both could miss the team's final eight games.

Headlining the list of additions is tight end Jordan Reed, who has been on injured reserve with a sprained knee suffered in a Week 3 victory against the New York Giants. From the practice squad, the Niners activated receivers Kevin White and River Cracraft, tight end Daniel Helm and safety Johnathan Cyprien with the designation of COVID-19 replacements.

In addition, the team elevated offensive lineman Tony Bergstrom and running back Austin Walter from the practice squad under the standard one-game elevation designation. They will revert to the practice squad after Thursday's game.

The moves at receiver come on the heels of a week in which the Niners have again been hit hard by injuries but are now also dealing with the fallout of Bourne's positive test. The Niners enter Thursday's game without any of the seven skill players who touched the ball in the team's Jan. 20 win in the NFC Championship Game against Green Bay on the active roster.

White and Cracraft join Trent Taylor and Richie James Jr. as receivers available to play against the Packers. James is listed as questionable on the injury report with an ankle issue but he was able to practice during the week and is expected to play against Green Bay.

Walter will complement JaMycal Hasty and Jerick McKinnon at running back, and Helm and Reed will offer more options at tight end with Ross Dwelley and rookie Charlie Woerner. Justin Skule is expected to start for Williams at left tackle.