A notice filed three weeks ago by prosecutors indicates plans to show that Ryder's alleged theft is part of a pattern of behavior, according to Reuters.
Los Angeles District Attorney spokeswoman Sandi Gibbons told Reuters, "We have filed notice of a motion to admit other acts. But we may or we may not file the motion, and we are not commenting at this point."
Beverly Hills Superior Court Judge Elden Fox ordered Ryder to stand trial last week after hearing testimony from a Saks Fifth Avenue security guard that she saw the actress kneeling on the floor of a fitting room using scissors to cut security sensor tags off handbags.
But Ryder's attorney claims the actress is being targeted because of her celebrity status and has accused Saks security staff of "lying through their teeth."
Ryder has pleaded not guilty to stealing $4,700 worth of designer goods from the Saks store in Beverly Hills last December. Among the 21 items she allegedly stole are a Gucci dress, a Dolce & Gabbana purse, a Marc Jacobs sweater, Calvin Klein socks and a Natori handbag valued at $3,595.
Ryder, 30, is due to be arraigned Friday on charges of burglary, grand theft, vandalism and possession of the painkiller Oxycodone without a prescription.