The San Francisco 49ers' roster is very healthy going into Super Bowl week, but the Niners appear to have some cause for concern with an injury that hindered their defense down the stretch of the regular season as they prepare to face the Kansas City Chiefs.

San Francisco held their first pre-Super Bowl practice on Thursday and absent was defensive tackle Arik Armstead.

Armstead missed the final five games of the regular season with knee and foot injuries. After being listed as a full participant in Wednesday's estimated practice report, it appears as if those issues are giving him some trouble again 10 days out from his second Super Bowl appearance.

49ers injury report

Player	Injury	Thursday
Arik Armstead	Foot, knee	DNP
George Kittle	Toe	DNP
Trent Williams	Rest	DNP
Oren Burks	Shoulder	Limited
Ambry Thomas	Ankle	Limited
Kalia Davis	Ankle	Full

Injury report observations

Head coach Kyle Shanahan did not indicate beforehand that Armstead would miss practice and, with Shanahan not due to speak again until Monday's Super Bowl Opening Night, little light is likely to be shed on his status until next week.

Armstead's injury was seen as a key reason why the 49er run defense declined over the final five weeks of the season. 

San Francisco has still struggled to defend the ground game even with their longest-tenured player back in the lineup. Still, with Armstead having impressed from a pass-rushing perspective with nine pressures in the playoffs, the Niners will be very keen to have him available against a Chiefs offensive line that could be without Joe Thuney.

Tight end George Kittle was listed as DNP on Wednesday and was predictably not involved on Thursday.

Asked if there was any concern of that injury, or if it was possibly turf toe, Shanahan was blunt.

"No, it's just a toe," he said.

The 49ers will practice again on Friday before traveling to Las Vegas on Sunday.

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An early tip to the officials.