"Early last season, Josh Johnson approached Rich Dubee at Citizens Bank Park with a modest request. The Marlins ace asked the Phillies pitching coach if he could stand and observe one of Roy Halladay's bullpen sessions.

Dubee turned to Halladay for permission.

"He told me, 'You can stay,' " Johnson recalled Monday. "I watched pretty intently."

Comparisons between Halladay and Johnson will continue as long as both carve through the National League. And because these two teams face each other 18 times a season, there is an off chance that baseball fans everywhere will be treated to a pairing of the two like Tuesday night.

"I still think Roy is the best pitcher," Shane Victorino said, "but you could arguably say Josh Johnson is in that category."

Twice in 2010, Halladay and Johnson opposed each other. Thirty-two innings thrown by the two righthanders yielded one earned run. One steamy night in May at Sun Life Stadium produced history - Halladay threw a perfect game, with Johnson the losing pitcher because of an unearned run.

So there are high expectations for the third meeting.

Halladay has a 2.19 ERA in seven starts, two of them complete games, with 57 strikeouts against seven walks. Since joining the Phillies, Halladay has lost one game against teams from the National League East. That defeat came June 10, 2010, against Johnson and Florida.

Johnson has a 1.68 ERA in seven starts with 46 strikeouts and 15 walks. He has allowed just 26 hits in 481/3 innings.

The righthander apparently has gained Halladay's respect. After the stoic Phillies pitcher permitted Johnson to watch his bullpen session, the two spent time together at the All-Star Game in Anaheim, Calif. When Johnson walked into the National League clubhouse, Halladay came up and said hello.

"Whoa," Johnson said. "This is, like, the Roy Halladay.""