The 21-year-old has scored 13 goals in 13 league appearances since joining Boro from Tottenham Hotspur, establishing himself as one of the division's most productive forwards and attracting attention from clubs higher up the football pyramid.
His return represents the best start to a season by a Middlesbrough player since George Camsell in 1926, underlining the impact he has made since arriving at the Riverside Stadium.
Newcastle United were reportedly due to send representatives to watch Lankshear against Wrexham on Wednesday, but the striker missed the match through injury. Middlesbrough went on to lose 2-0, ending their 11-match unbeaten run in the league.
Lankshear's performances had also brought him into consideration for a first senior England call-up.
Thomas Tuchel was keeping an eye on the striker ahead of the November international fixtures against Croatia and Spain, with England scouts expected to assess him during Middlesbrough's trip to Wrexham.
The forward had reportedly been included on England's 55-man long list, but his injury meant he was unable to take part in the match and ultimately miss out on the final squad.
His absence was a disappointment after a prolific opening to the campaign. Lankshear has already demonstrated his ability to score consistently at Championship level, having also found the net 11 times in 43 league appearances during his loan spell at Oxford United last season.
He joined Middlesbrough permanently from Tottenham in the summer, having made six senior appearances for the north London club and scored once, against Galatasaray in the Europa League.
Newcastle's interest comes as the club look to improve their attacking options. They have invested heavily in forwards since selling Alexander Isak to Liverpool, with reported spending of around £180million on attacking recruits.
Nick Woltemade, Yoane Wissa and Matias Fernandez-Pardo have all arrived in significant deals, but Newcastle are still being linked with further options as they seek greater consistency in front of goal.
Lankshear would represent a different type of target, with his age and current scoring record making him an attractive prospect. However, any attempt to prise him away from Middlesbrough would be complicated by the clubs' regional rivalry.
Boro will be reluctant to lose a striker who has become central to their promotion ambitions. Their defeat to Wrexham was the first time they had failed to score in the Championship this season, while their lead at the top of the table was cut to one point.
Lankshear is under contract at Middlesbrough for five years, and Tottenham did not include a buy-back option when agreeing his transfer.
His immediate priority will be returning to fitness and continuing his scoring form. If he does so, Newcastle's reported interest and the attention from England could make him one of the Championship's most closely watched players over the coming months.