Hoffman, 23, allowed six earned runs on seven hits in just 2.2 innings Monday for Triple-A Albuquerque.
That's the second time in four outings that Hoffman has surrendered at least six earned runs. He has failed to pitch more than five innings in four straight starts. After being considered for a promotion to the big leagues earlier this summer, Hoffman's ERA has risen from 2.67 on June 3 to 4.35 at present.