ALLEN PARK — Calvin Johnson, Louis Delmas and Bill Bentley did not practice today (Wednesday).

Chris Houston was back at work for the first time since he suffered a high ankle sprain in the third preseason game.

Johnson was on the field with his teammates, but had no helmet and was not working in individual drills. It could just be a day of rest for the veteran receiver. More information will be on the late-afternoon injury report.

Bentley suffered a concussion in the third quarter of Sunday’s win over the Rams. He must pass tests to be cleared for contact.

Delmas hasn’t practiced since Aug. 7 knee surgery.

The Lions, who haven’t won in San Francisco since 1975, play at the 49ers at 8:20 p.m. on Sunday.

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