The Mariners have claimed right-hander Isaac Mattson off waivers from the Pirates, MLBTR has learned. Pittsburgh hadn’t designated him for assignment, so it seems they instead quietly placed him on outright waivers at some point in the past couple days. Seattle’s 40-man roster is now four players over capacity, so they’ll need to subtract four players at some point prior to today’s deadline to get back down to 40.
More to come.