Siani (oblique) took a full round of batting practice Thursday, John Denton of MLB.com reports.
It's the first time he's done so since landing on the 10-day injured list in early August with a right oblique strain. Cardinals manager Oliver Marmol said Thursday that Siani will begin a rehab assignment soon, although the team is still determining when and where that will occur. The center fielder has a shot to return before the end of August.