The 49ers created an opening on their 53-man roster by waiving defensive tackle Demarcus Dobbs on Tuesday, but that spot won’t be filled by Aldon Smith this week.

The All-Pro outside linebacker won’t be reinstated a week early from his nine-game suspension and won’t be available Sunday against the Saints, ESPN reported. Smith, who reportedly could have returned early for good behavior, will be reinstated Monday and will make his 2014 debut on Nov. 16 when the 49ers visit the New York Giants.

Outside linebacker Dan Skuta, who has started eight games in Smith’s absence, sustained an ankle injury in a 13-10 loss to the Rams on Sunday and may not be available to play against New Orleans. Skuta was walking with a pronounced limp in the locker room Tuesday. Rookie Aaron Lynch would likely start if Skuta is not available.

Meanwhile, Dobbs, who joined the team as an undrafted rookie in 2011, was inactive Sunday. He has played 79 snaps in six games this season.

Even without Dobbs, the 49ers, who run a 3-4 defense, still have six defensive linemen on their roster. They will also have another when nose tackle Glenn Dorsey is activated. Dorsey, who tore his biceps in training camp, is on injured reserve with the designation to return and resumed practicing last week. On Thursday, defensive coordinator Vic Fangio said Dorsey is likely a “couple weeks” away from playing.

Among the 49ers’ six current defensive linemen are two 2013 draft picks – Tank Carradine and Quinton Dial – who have received scant playing time this season. Dial has played 42 snaps in six games and Carradine has only been active for one game.

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The 49ers re-signed cornerback Chance Casey to their practice squad about two months after they released him following a two-week stint with the team. Casey, 23, entered the NFL as an undrafted free agent in 2013 and spent last season on Oakland’s practice squad.

The 49ers had an opening on their practice squad after they promoted cornerback Leon McFadden to their 53-man roster last week.