Craig Morgan and Ben Pringle have rejected new contracts at Rotherham and will leave the club on free transfers.
Saido Berahino can leave West Brom "if the deal is right", says manager Tony Pulis.
The Magpies surged into fifth place at the end of the 2011-12 season after Papiss Cisse wasdrafted in during the January transfer window to partner Demba Ba in spectacular style.
However, Ba's departure for Chelsea 12 months later left Alan Pardew's men with a sizable gap to plug just as his Senegal international team-mate's form in front of goal deserted him.
Having survived his end-of-season meeting with owner Mike Ashley, Pardew embarked upon his summer break knowing the recruitment of at least one proven frontman was the main priority, and Joe Kinnear's subsequent and controversial arrival as director of football has done little to shift that focus.
Kinnear, who had already spoken to the manager, met chief scout Graham Carr last week to draw up a plan of attack and it is understood they have a series of names in their sights.
St Etienne's Gabon international Pierre-Emerick Aubameyang has been close to the top of Newcastle's list for some time, although they are not alone in that respect and big-spending Anzhi Makhachkala's interest is a complication.
The Dagestan club, who were dumped out of last season's Europa League by the Magpies, have the financial power to spark a bidding war in which Ashley will not become involved, and can also offer the 24-year-old European football next season, something their English counterparts cannot.
Vitesse Arnhem's Wilfried Bony has also been on the Magpies' radar, although competition seems certain to drive his price-tag up, while they have also been linked with Marseille's Andre-Pierre Gignac - although at 28, his £12million valuation is one which simply does not fit into the Ashley model.
Newcastle are also maintaining an interest in Aston Villa's former Sunderland frontman Darren Bent, who is desperate for a way out of the Midlands club after finding himself sidelined by rising star Christian Benteke last season.
On the face of it, the 29-year-old is another man whose CV makes him an unlikely target. However, he is vastly experienced and he scores goals, and both are qualities Pardew is keen to recruit.
That said, the deal would have to make financial sense for it to go anywhere, and that means any fee would have to be realistic - and perhaps significantly lower than the £6million which has been mentioned in despatches - and the player's own wage demands too would have to be in line with the salaries currently on offer at St James' Park.
While the final third may be Pardew's main priority, he will be keen to strengthen at the back too despite skipper Fabricio Coloccini's confirmation that he will be back for the new season after asking to leave in January.
The club's long-standing pursuit of FC Twente's Douglas appears to have stalled in the wake of Kinnear's arrival, but Newcastle were hit hard by defensive injuries last season and although Mathieu Debuchy, Massadio Haidara and Mapou Yanga-Mbiwa all arrived in January, a swoop for another central defender is still a distinct possibility.