Porter, 30, stayed on the ground for several minutes in the second quarter after absorbing a knee to the head from teammate Harold Jones-Quartey on a tackle attempt. He was immediately escorted back to the locker room and evaluated for a concussion.
"It was a funky play," Jones-Quartey said. "I came in there and could have possibly hit him. I'm just glad he's doing all right. But I saw him when I came in the locker room. He's going to be all right, or at least I hope so. Tracy is our leader and we look up to him. He's going to bounce back."
The Bears are thin at cornerback. Former first-round pick Kyle Fuller recently underwent arthroscopic knee surgery and is expected to miss the remainder of the preseason. The team has not said whether it expects Fuller to return for the regular-season opener against the Houston Texans on Sept. 11.
Former starting nickel back Bryce Callahan has battled injuries much of the summer as well.
Porter, whom the Bears re-signed in the offseason, successfully recovered from an injury-plagued one-year stint in Washington (three games played in 2014) to become arguably Chicago's most effective cornerback last season. He led the team with 22 pass breakups.
His crowning achievement in a Bears uniform happened in an upset victory at Green Bay when Porter became the only player to record four pass breakups against quarterback Aaron Rodgers in a single game.
'He's one of the leaders back there," Bears linebacker Danny Trevathan said. "We definitely need him. When he went down, I was just praying for him. I don't know what happened because it happened so fast. We need him. He brings a lot to the table -- leadership, athleticism, attitude ... everything he has."
The Bears return to practice Monday in advance of next week's preseason finale in Cleveland.