Pineiro (hamstring) did not participate in practice Thursday, Matt Barrows of The Athletic reports.
The kicker was diagnosed with a Grade 1 hamstring strain after suffering the injury during last Sunday's win over Arizona. The 49ers will likely need to sign another kicker if Pineiro can't go Monday against Carolina. Pineiro will have two more opportunities to practice before the 49ers formulate their final injury report ahead of the contest.