Volstad's Minor League deal included a clause allowing him to sign with a team in the Far East. Last offseason, the Angels lost veteran Jo-Jo Reyes to the SK Wyverns of the Korean League in a similar fashion.
One potential replacement for Volstad on the Angels' depth chart could be the 36-year-old, previously retired Mark Mulder.
Nick Cafardo of The Boston Globe reported via Twitter on Friday night that the Angels are "emerging as [a] front-runner" to acquire the veteran left-hander, adding that "an incentive-laden deal could be consummated soon."
Mulder, 36, has been retired for four years, hasn't pitched in the Majors since 2008 and currently works as an ESPN analyst. But the Angels were among the teams who saw him throw in Arizona just before the Winter Meetings, and a source confirmed that they have interest in acquiring the former A's and Cardinals stalwart.
A separate source told MLB.com that Mulder, who is set on coming back to pitch, is weighing offers from seven teams, including the Angels. Earlier reports said Mulder was seeking a Major League contract, but it remains to be seen if he actually gets that.
Volstad was the 16th-overall pick by the Marlins in 2005 and had a solid rookie season in '08, posting a 2.88 ERA in 15 games (14 starts) -- but he hasn't been able to duplicate that.
Over the next four big league seasons, the last of which was spent with the Cubs in 2012, Volstad compiled a 5.14 ERA and averaged 153 innings per season. Last year, he spent the vast majority of the season -- minus six relief appearances -- pitching for the Rockies' Triple-A affiliate in the Pacific Coast League, posting a 4.58 ERA, a 1.57 WHIP and a 1.30 strikeout-to-walk ratio in 127 2/3 innings.
The Angels' priority for the Major League rotation remains Matt Garza or Masahiro Tanaka.
Alden Gonzalez is a reporter for MLB.com. Read his blog, Gonzo and "The Show", and follow him on Twitter @Alden_Gonzalez. This story was not subject to the approval of Major League Baseball or its clubs.