Chicago Bears rookie safety Jaquan Brisker is out indefinitely after undergoing surgery on his right thumb

Chicago Bears safety Jaquan Brisker had surgery this week on a broken right thumb and will be out into September, according to sources.

Bears coach Matt Eberflus said Saturday after training camp practice that the team has “no timetable” for Brisker’s return. But there appears to be optimism he could be back for the team’s Sept. 11 season opener against the San Francisco 49ers.

Still, the injury is an unfortunate setback. Brisker, who was drafted with the No. 48 pick in April, had been enjoying a productive camp and showed flashes of promise during the team’s preseason opener against the Kansas City Chiefs. But somewhere within that game, Eberflus said, the safety injured his right hand without initially realizing the severity.

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“Sometimes you wake up with these hand injuries and it just shows up,” Eberflus said. “It feels like you just kind of tweaked (something) a little bit. And all of a sudden the next day, there it is. So it was one of those deals.”

Brisker did not practice last week and missed the team’s 27-11 victory over the Seattle Seahawks on Thursday night. His return to practice isn’t expected in the next two weeks.

The Bears will play their preseason finale Saturday against the Cleveland Browns but then have a one week bridge before Week 1 begins.

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Eberflus indicated Saturday that Bears coaches weren’t yet sure how much their starters might play against the Browns — if they play at all. He was asked whether the injury to Brisker could affect his thought process, possibly pushing him to be more cautious.

“I don’t think so,” Eberflus said. “We’ll just plug and play like we always do, and I don’t think that will affect it one way or the other.”