SANTA CLARA – Defensive lineman Arik Armstead, who has appeared in just 14 games over the past two seasons, is likely to miss multiple weeks of training camp with a hamstring injury.

On a day the 49ers activated five players off injury lists, the club announced Armstead, the 49ers’ first-round draft pick in 2015, will be sidelined on a “week-to-week” basis. Armstead is scheduled to start at defensive end this season.

The five players the 49ers cleared to begin practicing are: guard Jonathan Cooper, receiver Trent Taylor, safety Marcell Harris, and linebackers Malcolm Smith and Dekoda Watson.

Rookie defensive lineman Kentavius Street, who sustained a torn ACL in a pre-draft workout with the New York Giants, remains on the non-football injury list and is likely to sit out the entire season.

Cooper enters the competition for the starting job at right guard. Joshua Garnett, who is also competing for the job, missed practice on Sunday due to a knee contusion. He remains “day to day,” the 49ers announced.

Second-year tight end Cole Hikutini (groin) will sit out of practices this week and could be brought back to the practice field next week.