Weepu strained a thigh muscle in training, but proved his fitness later in the week.
Southland scrum-half Jimmy Cowan, called up as cover, returns to Invercargill for the NPC game against Otago.
Leon MacDonald's availability will be re-assessed with a decision on the injured first five-eighth expected only at match time.
Auckland full-back Brent Ward has been called into the squad as a potential replacement.
Coach Graham Henry selected Ward over other contenders, such as Wellington first five-eighth Jimmy Gopperth, for his goalkicking abilities.
Should MacDonald miss the game, versatile Blues and North Harbour back Luke McAlister is expected to step into the starting XI.