49ers backup LB Curtis Robinson carted off practice with a knee injury

The 49ers can't catch a break . . . unless it's a literally break.The team saw three players return to the practice field Thursday, but before the session even began, the 49ers lost another player.Backup linebacker Curtis Robinson was carted off the field during special teams work, Matt Maiocco of NBC Sports Bay Area reports.The 49ers' practice report shows Robinson has a knee injury.Robinson, a core special teams player, was a candidate for a bigger role on the defense this week. He played 59 special teams snaps and none on defense in the first three games.Robinson has one tackle.Wide receiver Deebo Samuel (calf), left tackle Trent Williams (illness) and linebacker Dee Winters (ankle) returned to practice Thursday.