Man United Very Serious About Signing $66million Attacker – Miki's Replacement?

Manchester United splashed heavy cash in the summer transfer window to sign Henrikh Mkhitaryan from Borussia Dortmund.
However, the Armenian international has only started one game under the management of Jose Mourinho and already he is linked with a move away from Old Trafford.
Moreover, reports in the Portuguese media (A Bola) suggest that United are very serious about signing Sporting CP attacker Gelson Martins. It will not come as any surprise if he replaces Miki.
The 21-year-old impressed is mainly a right winger who impressed big time last season and manager Jorge Jesus has made him a regular starter this season.
Last season, he scored 7 goals and provided 4 assists in 42 games. This time around, Gelson has directly contributed in 9 goals (2 goals and 7 assists) in 9 league appearances so far in the current campaign.
Martins has played two games for the senior national side and has a release clause of 60 million euros ($66million) in his contract (SW)
As per the provided A Bola link, Man United have scouted the Portuguese international in more than a dozen games.
In your opinion, should United sign Gelson Martins?