The Spaniard has been linked with a £20m switch to Everton.
It was reported by The Telegraph this week that Everton were weighing up a £20 million offer for the 28-year-old, who looks to be on borrowed time at Old Trafford following the arrival of Jose Mourinho, having already sold him once in his career during their time at Chelsea.
Should the switch to Goodison Park materialise, the Spain international may well compete with Ross Barkley for the number 10 role.
One of the reasons Mourinho may have sold him could be related to his work ethic and defensive contributions, and Hislop feels Mata may hold Everton back in this regard if he does indeed move to Merseyside this summer.
"Mata is as creative [as Barkley] but as far as defensive responsibility goes he can be a little bit of a liability," he told ESPN.
Signing Mata would certainly be an excellent way for Ronald Koeman to announce himself as Everton manager, having replaced Roberto Martinez last month.
The Dutchman has already taken goalkeeper Maarten Stekelenburg with him to the Toffees, but he is hardly the sort of marquee name that fans would've been dreaming of when it was reported by The Telegraph that Koeman would have £100 million to spend.
Still, there's plenty of time in which to fully utilise that warchest and supporters will be hoping he does just that.
New manager Ronald Koeman during the press conference