The Padres have designated lefty Matt Thornton for assignment, Dennis Lin of the San Diego Union-Tribune tweets. The move clears space for new addition Clayton Richard.
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The 39-year-old Thornton signed a minor league deal with the Padres last offseason. He missed most of the first two months of the year with Achilles tendinitis, then struggled in 17 innings with San Diego, posting a 5.82 ERA, 4.8 K/9 and 3.2 BB/9. His velocity has dropped from the mid- to high 90s as a member of the White Sox several years ago to 91.4 MPH this year, likely a key factor to his steadily declining strikeout rate over the past few seasons. He has a 3.41 ERA, 8.7 K/9 and 3.4 BB/9 in parts of 13 years in the big leagues.