Disclosed are compounds of Formula (I) or salts thereof, wherein: HET is a heteroaryl selected from pyrazolyl, indolyl, pyrrolo[2,3-b]pyridinyl, pyrrolo[2,3-d]pyrimidinyl, pyrazolo[3,4-b]pyridinyl, pyrazolo[3,4-d]pyrimidinyl, 2,3-dihydro-1H-pyrrolo[2,3-b]pyridinyl, imidazo[4,5-b]pyridinyl, and purinyl, wherein said heteroaryl is substituted with Ra and Rb; and R1 and R2 are define herein. Also disclosed are methods of using such compounds as modulators of IRAK4, and pharmaceutical compositions comprising such compounds. These compounds are useful in treating, preventing, or slowing inflammatory and autoimmune diseases.