Mariners Acquire David Aardsma By Tim Dierkes | January 20, 2009 at 4:50pm CST According to Ryan Divish, the Mariners acquired reliever David Aardsma from the Red Sox for minor league lefty Fabian Williamson. Aardsma had been designated for assignment on Thursday. Aardsma, 27, posted a 5.55 ERA in 48.6 innings for the Red Sox last year. Control was a problem, but he did rack up Ks. Aardsma’s average fastball velocity was 94.5 mph.