The early shift may be tough (8)
'tough' is the definition.
'the early shift' is the wordplay.
'shift' indicates an anagram.
'theearly' is an anagram of 'LEATHERY'.
'may be' is the link.
(Other definitions for leathery that I've seen before include "rather tough", "Tough textured", "Tough, wrinkled (skin)", "Tough-textured", "Like tough skin".)