Venables is the latest Eagles forward to suffer a setback after after the exciting newcomer injured his ankle late in the third term of West Coasts 80-point destruction of Gold Coast on Saturday.
Eagles medical staff will examine results of scans on his right ankle on Monday, with the emerging youngster tipped to miss at least a fortnight, despite being spotted walking in the changerooms immediately after Saturday night's big win.
Venables, 19, is not likely to have suffered anywhere near the amount of damage that will sideline exciting first-year forward Liam Ryan for three months.
West Coast has debuted Ryan, Venables, Jake Waterman and Willie Rioli with predominantly forward line duties in its thrilling opening to 2018.
Counting against Ainsworth debuting is that he has not played a match for the past fortnight, after named as emergency last week against Geelong and alignment team East Perth having a bye in the WAFL this week.
Ainsworth played some impressive senior footy at powerful WAFL unit Subiaco before he was plucked by the Eagles with their fourth pick in last years national draft and 32 overall, with the speedy Petruccelle taken at 38.
Other recall options for West Coast include recognised defender Tom Cole or veteran defender Will Schofield if Sheppard is ruled out.