"Josh Johnson is so enamored of Roy Halladay that he followed him around like "a little brother" at last year's All-Star Game and asked for permission simply to watch the Phllies ace throw a bullpen session during a Marlins trip to Philadelphia last season.

"I watched pretty intently," Johnson said.

But Johnson said he won't be paying one bit of attention to his counterpart when the two hurlers — two of the elite pitchers in the majors — square off at Sun Life Stadium on Tuesday.

"If I start worrying about who's over there and what he's doing, then that's not focusing on what I'm doing," Johnson said. "That's when you get in trouble."

It will be the first time the two aces have gone head to head in South Florida since Halladay not only outdueled Johnson in a 1-0 Phillies win last May 29, but also recorded the 20th perfect game in major-league history. The only run was unearned, the product of a Cameron Maybin error.

"It was a heavyweight bout," said Marlins reliever Brian Sanches.

Another could be in store Tuesday when the two pitchers go head-to-head for the fourth time. Johnson has won the other two meetings, the first in 2006 when he was a rookie and again last June."