According to the Daily Express, Martinez had a £35m valuation earlier this summer but Porto will now accept as little as £16m for his services.
Arsenal, Manchester United and Chelsea have all been linked with the Colombian international since the end of last season, and could now be tempted to try their luck with a bid for the forward.
Competition for Martinez?
But they will not be the only interested suitors, especially at that price. Roma and AC Milan are ready to offer Martinez a route to Serie A although neither Italian club have the financial resources to match the Premier League giants when it comes to wages.
Arsenal remain the most likely destination despite Arsene Wenger's insistence that he does not need to sign another forward this summer. Most Gunners fans would like to see another striker brought in, as Olivier Giroud is still the club's only recognised senior player at the position.
Joel Campbell plays predominately from out wide, while Theo Walcott can play down the middle but is an inconsistent finisher and is currently injured. Based on last season, Yaya Sanogo does not look ready to step up for the first-team on a regular basis.
But don't count Manchester United out, as Louis Van Gaal confirmed once again last night that he intends to play two strikers up front next season.
Van Gaal's new formation
The Dutchman trialled a new 5-3-2 formation with wing-backs against LA Galaxy last night, and United looked excellent as they beat LA Galaxy 7-0. Van Gaal has plenty of options already, including Wayne Rooney and Robin Van Persie, while Javier Hernandez is a top impact substitute - although it's not a role he enjoys.
Should he leave, United may enter the race for Martinez. As mentioned earlier, Chelsea are also admirers of Martinez and have a good relationship with Porto having bought many players from the Portuguese club before, including Deco, Ricardo Carvalho and Maniche over the years.
Having played at the World Cup, Martinez has delayed his return to Porto amid the transfer rumours.