The Aberdeen-based firm’s market capitalisation ranks it at the lower end of the blue-chip index, along with mining company ENRC and outsourcing specialist Serco.
Wood Group was promoted into the top flight in September 2012, having been relegated a year earlier.
The company has yo-yoed between the FTSE 100 index and the FTSE 250 index in recent years.
Winning a place in the FTSE 100 often boosts demand for a stock because it is then included in tracker funds.
If Wood Group does lose its space in the premier division, then it could be to South African paper maker Mondi.
Sports Direct, the clothing retailer run by Newcastle United football club owner Mike Ashley, and Coca-Cola Hellenic – the soft drink bottler that moved its listing from Athens to London earlier this year – are poised for promotion into the top flight, although all moves depend on trading in the next three days.
Being elevated into the FTSE 100 for the first time would kick off an important week for Sports Direct, which is due to unveil a trading update at Thursday’s annual general meeting (AGM).
The stock has leapt more than 70 per cent since the start of the year, with record full-year profit cheering investors.
Retail analyst Nick Bubb said: “Wednesday could be a red letter day for Sports Direct, after its AGM trading update and the announcement of the latest quarterly FTSE index review.”