Seattle Mariners starting pitcher Erik Swanson (hamstring) went on the injured list on Friday with a hamstring issue in the minors. Swanson, the team's No. 9 prospect per MLB Pipeline, struggled in six starts and one relief outing for the M's earlier this year, going 1-5 with an 8.04 ERA, 1.44 WHIP, five walks and 24 strikeouts in 31 1/3 innings. He's been better at Triple-A Tacoma with a 4.09 ERA, 1.46 [...]