The Spain international moved to the defending Premier League champions in a £58m deal from La Liga giants Real Madrid in the 2017 summer transfer window.
Morata hit the ground running with eight goals in his opening seven games to appear to make a swift adjustment to the Premier League.
The 25-year-old has since struggled to maintain his start to life at Chelsea FC to raise questions about his suitability to the English top flight.
Indeed, Morata has only scored five times in his last 24 games in all competitions to result in his omission from the Spain national team.
Chelsea FC’s decision to sell Diego Costa to Atletico Madrid last summer and place their faith in Morata has appeared to backfire.
Former Newcastle and West Ham goalkeeper Hislop believes Morata isn’t at the sufficient standard to play for Chelsea FC.
“You start the season fantastically well, you’ve got the confidence of the manager and everything is going great,” Hislop told ESPN FC.
“You then have this dip in your confidence and it’s about responding to that.
“The old cliche is you just need one to come off the knee, one to come off the backside or you need the goalkeeper to flap and you head it in. Then you build from that.
“But you don’t see that from Alvaro Morata. Regardless of what league you’re playing in, if you can’t build on those gifts, then you’re not good enough.”
Chelsea FC have won the Premier League title in two times in the past three seasons.
The Blues signed Everton playmaker Ross Barkley, AS Roma defender Emerson Palmieri and Arsenal striker Olivier Giroud in the January transfer window.
Chelsea FC will take on Southampton in the FA Cup semi-finals later this month.
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