Taschner, who recently rejected an outright assignment by the Pirates and became a free agent after returning from a left hamstring injury, allowed a solo home run to Allen Craig of Memphis in his Albuquerque debut on Sunday.
That game was started by another former Major Leaguer, Claudio Vargas, whose transformation back to a starter suffered a major setback when he was shelled for seven earned runs and five extra-base hits in only 2 2/3 innings.
Taschner is being viewed as a possible situational left-handed alternative because of the season-long slump of lefty George Sherrill and the fact that Hong-Chih Kuo is not being used on back-to-back days because of his brittle elbow.
In 17 appearances for Pittsburgh this year, Taschner had a 6.05 ERA. He has also pitched for the Giants and Phillies, posting a career 10-5 record and a 5.10 ERA.
"We want to see what we have here," said manager Joe Torre. "I still think highly of Sherrill; I know what he's capable of doing. It's still a matter of getting his confidence back. He's still feeling for it."
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.