Whalen (shoulder inflammation) was placed on the 10-day disabled list Friday.
The Mariners made their final round of roster moves Friday to trim their roster down to 25 active men and were able to do so by placing six different players on the DL, including Whalen. The 23-year-old has battled a calf injury this spring and he's now experiencing some inflammation in his throwing shoulder. It's unclear when exactly he'll be ready to come off the disabled list, but Friday's announcement guarantees he'll miss at least the first week and a half of the season.