49ers RB Chris Johnson misses first preseason practice

The 49ers are still trying to find their groove after their first practice back in the preseason, but they’ve got one more chance to get it right before the start of the regular season.

On Monday, they’ll be joined by a veteran running back.

Running back Chris Johnson missed practice Monday with a knee injury.

Johnson missed his first preseason game against the Tampa Bay Buccaneers with an injury to his right knee.

He practiced Tuesday and Thursday.

If he does play in the opener against the Detroit Lions on Oct. 31, Johnson will be the first running back in 49ers history to miss at least 10 games in his first year of eligibility.

The 49ers also have to decide on the roster for next year’s draft, which will be held on Sept. 27.

They’ll have to wait until then to make a decision on a first-round pick.