Helman (undisclosed) is back on the 7-day injured list with Triple-A St. Paul.
He missed time earlier this year with a hamstring issue, so he may have aggravated that injury. Helman, who just turned 27, has hit .333 with a .434 OBP, four home runs, two steals and a 13.2 percent strikeout rate in 12 games at Triple-A this season.