In a posting Monday on Caring Bridge, a Web site that shows updates on patients' conditions for family members and loved ones, Sandberg's sister Kalli said her brother "is improving more and more every day."
Sandberg, a junior at Marin Catholic, was put into a medically induced coma and a portion of his skull was removed to alleviate swelling in his brain. He is now recovering at a rehabilitation hospital in San Francisco.
In her post Monday, Kalli Sandberg said her brother is continuing to gain back the weight he lost and is walking on his own with supervision. He still has to wear a helmet whenever he gets out of bed, but is expected to come home from the hospital May 3.
Once he is released, he will continue to have outpatient therapy. He will also be working with people who will help improve his memory and help him catch up on his schoolwork, his sister said.
She said his family is hoping he will be ready to start his senior year this fall.
The incident revived a controversy about the use of metal bats, which some say are more dangerous than wooden bats. Marin Catholic and other teams in the Marin County Athletic League stopped using metal bats until the end of the season.
A number of restaurants in Marin and Contra Costa counties agreed to donate a portion of last Saturday's proceeds to a fund for Sandberg. The fundraising effort was started by players at De La Salle High School in Concord, the team that was playing Marin Catholic when Sandberg was injured.
Rick Steen, De La Salle's baseball coach, said he will be collecting checks over the next day or two from the restaurants that participated. He said one restaurant raised $1,425.
The fundraiser was dubbed 4/17 for .17, Sandberg's jersey number. Proceeds will be deposited into an account for Sandberg at the Bank of Marin.