The gulf in his white and red ball output is stark. He averages 41.16 in ODIs, top scored in the World Cup last summer and has nine centuries.
His test average is 28.52. In his last nine first innings' in tests, the 29-year-old has scored 102 runs, reaching double figures three times. He's scored two half centuries in his last 21 test innings.
"My recommendation would be the guy is a class act and yes he hasn't reached where he and we want him to reach," McCullum said last night.
"But there's so many cases now where see successful short version players, especially at top of the order who are able to transition into successful test players."
McCullum said Guptill, who was dropped from the test team for two years in 2013 until earlier this year, had been working hard on his defence.
"The next step is being able to forget about that work on defence and play your natural game.
"I think we'll see over the next little while a guy who probably starts to gravitate towards his one-day game and trusts the defensive work he's been doing."
Taylor also supported Guptill's credentials.
"He hasn't scored as many runs as he would like," Taylor said.
"He's still trying to find that happy medium between red and white ball cricket.
"He's got an amazing one-day record but he's missed out here a couple of times."
Taylor said Guptill's work ethic around his batting was impressive but ''sometimes it doesn't transition into runs".
Taylor insisted Guptill, who has played 36 tests for two centuries, against Bangladesh and Zimbabwe, had the game to succeed at test level.
"He got a couple of 70s in England in tough conditions opening with the ball swinging a lot in May.
"He has got a technique that can survive at this level but we haven't seen it, disappointingly, here in Australia."
The selectors have shown faith in Guptill. It's being tested again, but he is likely to get another chance in home conditions against the less threatening Sri Lankans.
