Sako, currently away at the African Cup of Nations, has been one of Wolves' biggest stars this season but only has six months left until his contract with the Championship club expires.
West Brom, meanwhile, are seeking a pacy winger to add to their ranks, say the Mail.
Aston Villa were linked with a similar bid for Sako earlier this season, which would have proved as surprising as West Brom's current reported interest.
Sako, 26, has been in good form for Wolves so far this campaign and Premier League interest in the Mali international is no shock. The fact that Wolves' Black Country rivals are looking to prise Sako away from Molineaux is certainly sure to cause a stir, however.
Tony Pulis has had a positive effect since taking over at West Brom, beating Hull City in the top flight before drawing 0-0 at Everton. The Welshman is yet to reveal his full hand in the transfer market, however, and bringing one of Wolves' best players to West Brom would certainly be an eventful way to kick-start his Hawthorns tenure.