Armstrong (oblique) played catch Monday, Greg Johns of MLB.com reports.
Armstrong is apparently recovering well from his Grade 1 oblique strain, as he made 25 throws at 70 feet Monday and will advance to 90 feet Tuesday. While the right-hander remains without a timetable for his return, he's optimistic he'll be ready to return shortly after his 10-day IL stint is up. Once healthy, he figures to fill a setup role for the Mariners.