San Francisco 49ers

Jim Tomsula narrows list of 49ers’ cornerback possibilities

Denver Broncos tight end James Casey (80) is hit by San Francisco 49ers cornerback Kenneth Acker (20) and Corey Lemonier (96) during the first half of an NFL preseason football game, Saturday, Aug. 29, 2015, in Denver.
Denver Broncos tight end James Casey (80) is hit by San Francisco 49ers cornerback Kenneth Acker (20) and Corey Lemonier (96) during the first half of an NFL preseason football game, Saturday, Aug. 29, 2015, in Denver. AP

Coach Jim Tomsula on Tuesday didn’t say which 49ers cornerback will start opposite veteran Tramaine Brock in Monday’s opener against the Minnesota Vikings, but it’s clear it will be a first-time starter.

Tomsula said Kenneth Acker and Keith Reaser, both of whom missed their rookie seasons last year because of injuries, were “in the mix” for the spot. Another player from the 2014 draft, Dontae Johnson, is expected to be the cornerback who enters in the nickel defense. In those instances, Brock will cover the slot receiver and Johnson will remain on the outside.

Later in Tuesday’s news conference, Tomsula seemed to suggest Acker had the lead. Asked if Acker and Reaser were competing for the starting role this week, he said, “Yes and no. Acker has done a great job, but Reaser is in the mix.”

Reaser is perhaps the most physically gifted of the 49ers’ cornerbacks. He was a track star in high school and is a cousin of late Washington safety Sean Taylor. He missed last season after dealing with complications from an ACL tear a year earlier at Florida Atlantic.

Acker was placed on injured reserve before the 2014 regular season because of what he said was a stress fracture in his foot. He had a strong exhibition season a year ago and an even better one this year that included an end-zone interception of the Denver Broncos’ Peyton Manning in the third exhibition game.

“I didn’t even know they missed all that time when I first got here,” said wide receiver Torrey Smith, a free-agent acquisition in March. “That says a lot about what they did rehab-wise to get to where they are.”

Asked what stood out with Acker and Reaser when he went against them in practice, Smith said both are very smooth in how they change directions and adjust to receivers.

“That probably stands out the most about them,” Smith said. “And their confidence, which probably means more than anything. Especially at their position. Because there’s going to be some times where receivers are going to make plays, and they’re going to have to be able to bounce back. And they’re new, so quarterbacks might try to pick on them.”

If Brock, Acker, Reaser and Johnson are the top four cornerbacks, it raises the likelihood that No. 5, Shareece Wright, could be inactive on game days.

Tomsula also would not name the punt returner, a job that could go to Reggie Bush, Bruce Ellington or rookies Jarryd Hayne or DeAndrew White.

91 New jersey number of rookie defensive lineman Arik Armstead, who switched from 69

Nine captains – The players voted on team captains. On offense, they are left tackle Joe Staley, receiver Anquan Boldin, tight end Vernon Davis and quarterback Colin Kaepernick. On defense, they are safety Antoine Bethea, linebacker NaVorro Bowman, safety Eric Reid and nose tackle Ian Williams.

The special-teams captain is kicker Phil Dawson.

Tomsula said the captains would not wear stars on their jerseys, as some teams do.

“No stars,” he said. “I’m into a team game.”

Tomsula’s predecessor, Jim Harbaugh, didn’t like the stars, either. He said stars belong on hockey sweaters, not football jerseys.

Hope you use that Ivy League degree.

Coach Jim Tomsula on new center Nick Easton from Harvard learning the 49ers’ offense

Et cetera – Rookie defensive lineman Arik Armstead changed his number from 69 to 91. Defensive end Glenn Dorsey will wear No. 90 instead of 91. Acker and rookie running back Mike Davis wore No. 20 in the exhibition season; Davis has switched to No. 22.

▪ Tomsula said tight end Vance McDonald, who had been dealing with an ankle injury, looked good in a recent practice. “I’m not sure where they’ll put him (on the injury report),” he said. “(But) I’m not even thinking about him.” The coach added he didn’t think Brock, who strained a hamstring in Denver, would be on the injury report.

▪ Tomsula said new center Nick Easton, acquired from the Baltimore Ravens on Saturday, had “some work to do” as far as studying the offense so he could be in uniform Monday. Easton is an undrafted rookie from Harvard. “Hope you use that Ivy League degree,” Tomsula advised.

Matt Barrows: @mattbarrows, read more about the team at