Mickelson shot a third-round 67 at Augusta to move into contention for a fourth Green Jacket, but a late birdie from Justin Rose meant the American would not be partnering Spieth on Sunday.
Rose moved within four shots of Spieth with a 67 of his own, and Mickelson will instead play alongside Charley Hoffman as he tries to make up five strokes on the youngster who has led the tournament from Thursday’s opening round.
But Mickelson insisted he did not mind being in the penultimate group, as he said: “I think in 2012 when I was in the final group watching (Louis) Oosthuizen and (Bubba) Watson in front of me make birdies, it was a lot harder to follow suit.
“I was hoping to be the group in front and if I can start posting some??birdies, I think it’s much more difficult to follow than it is to lead.
“Granted,??I’ve got a lot of work to do tomorrow and I’m quite a ways back, a good round??though and it could be fun.
“I don’t think it matters who is close to him (Spieth). I think he’s playing??very good golf and I think he’ll have a good round tomorrow.
“I think that if he were to come out on top, it would be great to have him in??the Champions’ Dinner every year. He would just be a great champion.
“He’s just a classy guy. He just represents the game very well and at a very??young age and he’s just got a lot of game. So if he were to come out on top, it??would be wonderful for the tournament, wonderful for the game.
“I’m going to try to stop him, but we’ll see how it goes.”