The Giants have designated left-hander Travis Blackley for assignment, according to Andrew Baggarly of CSN Bay Area (on Twitter). In corresponding moves, Jeremy Affeldt has been activated from the disabled list, Conor Gillaspie has been optioned to Triple-A, and Charlie Culberson has been recalled.
The 29-year-old native of Australia signed a minor league deal with the 2010 World Series champions this past February and appeared in only four games. Blackley totaled five innings and allowed five earned runs, walking two and striking out two as well.
Originally signed by the Mariners as an international free agent in 2000, Blackley has just 39 2/3 innings of Major League experience. He's struggled in the big leagues, amassing a 9.30 ERA, 6.6 BB/9, and 5.2 K/9. He's fared better in the minors, where he has a 4.54 ERA over 589 Triple-A innings. The San Francisco Chronicle's Henry Schulman tweets that Blackley likely will stay in the organization.