Results were not expected Wednesday.
"We encourage it," Phillies assistant general manager Scott Proefrock said of the second opinion. "It just provides him further peace of mind."
After conferring with Altchek, Phillies physician Michael Ciccotti and the Phillies' athletic training staff, Halladay is expected to meet with reporters sometime before the end of this weekend's series against the Miami Marlins at Citizens Bank Park.
The Phillies said Halladay will be sidelined from activities for three weeks, but they hope he can be back on the mound in six to eight weeks.