And the former England and Liverpool midfielder has warned the Red Devils they will 'finish worse than they did last season' if they sign him to play alongside Bruno Fernandes.
United are reportedly leading the race to sign the Denmark international this summer.
Eriksen is said to be considering an offer to join the Old Trafford club, with The Times claiming both Tottenham and Brentford have been 'left in the dark' over his future.
It's claimed Spurs have not heard anything from Eriksen's camp for the past two weeks, after making an offer to re-sign their former midfield star.
Brentford also have also no clue about Eriksen's plans, with the Bees keen for him to stay after his six-month deal expires on June 30.
Eriksen has a close relationship with Brentford boss, and fellow Dane, Thomas Frank, but also has a connection to new Manchester United manager Erik ten Hag, having trained with Ajax's reserve team at the start of the year as he prepared for his football comeback.
Ten Hag is said to be keen to sign Eriksen this summer as well as Frenkie de Jong, with negotiations with Barcelona over a deal for the Netherlands international thought to be at a 'key stage'.
But Murphy has questioned why the new United boss needs both players.
The former Tottenham and Liverpool star insists Eriksen should join a team where he will be guaranteed regular football, and wonders where he would fit in United's first XI.
"If you look at the Manchester United option, I don't see that," the former Liverpool and Tottenham midfielder told White and Jordan.
"If Ten Hag thinks he's going to play Eriksen and Fernandes in the same team in the midfield with only one holding player, they'll end up finishing worse off than they did this season.
"Unless he's going to bring him in as back-up to Fernandes to play as a No.10, or is he going to play him as a central midfielder?
"If you're talking about bringing De Jong and Eriksen in, where's the legs, where's the tenacity, where's the tough tackling and physical presence? There isn't one!
"It's a strange one for United why they'd want Eriksen, I don't get that. They've got enough attacking players and creative players.
United think getting someone who has been at Brentford and was one of Tottenham's main players in the past, in an unsuccessful team that won nothing, they think bringing Eriksen in is going to make them more competitive?
"If you're Eriksen and you get the chance at this stage of your career to play for Manchester United, look, you do it.
"But what should be the most attractive option for Eriksen this summer? It depends where he's going to play the most."