Saido Berahino has been the subject of intense transfer speculation over the past two seasons.
The newspaper claims that Berahino could be available for as little as £10 million with his contract set to expire next summer.
Ighalo has been by far the most prolific out of the two this season, scoring 16 goals in 39 appearances for the Hornets, while Berahino has managed to find the net only seven times in 32 outings.
It would, however, be a like for like replacement, if the Nigerian were to move from Vicarage Road, with both strikers game's based on movement and pace.
Both teams sit comfortably in mid-table in the Premier League, although Watford have suffered a disastrous run of form since the turn of the year, managing only four victories in the league.
West Brom drew 1-1 with Bournemouth today, whilst Watford make the trip to Anfield tomorrow.