Three potential starters who missed the 49ers’ game last Thursday were on the field Tuesday as the team came out of its “mini bye” weekend.
Tight end Vance McDonald (hip) missed the past two games while defensive linemen Glenn Dorsey (knee) and DeForest Buckner (foot) were unable to play in Thursday’s loss to the Cardinals.
The 49ers allowed 157 rushing yards to Arizona running back David Johnson in that game, a recurring theme this season for a defense that ranks 31st in average rushing yards allowed.
Defensive coordinator Jim O’Neil said Tuesday that was his greatest concern and that he and his staff spent the past few days figuring out what the defense has done well, what it hasn’t and honing the approach accordingly.
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“This defense is eight wins, no losses – let’s call more of that. This defense is six losses, two wins – let’s not call that as much, you know what I’m saying?” O’Neil said. “We have had four or five mental mistakes in this defense – hey, our guys aren’t doing a great job understanding that – whereas this defense we’re executing at a high level. It’s just, ‘Where are you going to shift your emphasis on what your guys do well and what they understand?’ ”
O’Neil has spoken previously about moving Dorsey, who is coming off an ACL injury, to nose tackle. The veteran defensive lineman did not play against the Cardinals because his knee didn’t feel right as he got ready to play on a short week.
“I think that’s one of the tough things when you transition and play a short week is sometimes guys like that that are coming off of injuries that are a little bit older, it’s a difficult deal,” coach Chip Kelly said of Dorsey. “I would imagine if we had a chance to play, if it was a Sunday to Sunday deal, that Glenn would probably be ready by the time we got to Sunday.”
Brock backed – O’Neil said he hasn’t lost faith in cornerback Tramaine Brock, who has given up two touchdowns in each of the past two games.
O’Neil said that Brock often draws the toughest assignments, such as covering Cardinals wide receiver Larry Fitzgerald.
“I’m not down on him at all,” O’Neil said.
Rookie cornerback Rashard Robinson has started the past two games at cornerback opposite Brock in place of injured Jimmie Ward. Robinson played well in his short stint as starter, allowing just 31 receiving yards.
Ward, meanwhile, was running at close to full speed Tuesday after injuring his quadriceps Sept. 25 in Seattle. He appears to be in position to return to the lineup in the coming weeks, perhaps after the 49ers’ bye on Oct. 30.