VIERA, Fla. -- Nate Robertson never really fit the profile of a stereotypical left-handed pitcher when the Tigers called him up six years ago. He might end up more like one now that he's older.

A day after Tigers manager Jim Leyland talked about Robertson defining what kind of pitcher he is now, pitching coach Rick Knapp provided a little more definition on what kind of pitcher they're working with him to become.

"I think that Nate needs to be more left-handed," Knapp said. "I think [Saturday] he took strides to that."

He isn't talking about which arm. He means how Robertson pitches with the arm he's got.

There are stereotypical crafty left-handers, such as Philadelphia's Jamie Moyer or Atlanta's Tom Glavine. There are also left-handers that can, and will, pitch inside in order to set up outside pitches. Knapp and the Tigers aren't quite trying to get Robertson to be a finesse lefty, but they're trying to get him further from the form with which he struggled last season.

"I want him to be himself," Knapp cautioned. "I just want him to be a hybrid version of himself."

By claiming the inside of the plate early and attacking it, Robertson gained a reputation early in his career as someone who pitched like a harder thrower than the velocity would read. He threw well into the lower-90's, with the mentality of a power pitcher and the strength of a power slider.

Robertson hasn't displayed the same velocity as past years, and while his hit rate has always been high, his strikeout rate has fallen, from 6.03 per nine innings in 2007 to 5.76 last year. Robertson's working to regain his slider, while Knapp and bullpen coach Jeff Jones are working with him to put the package around it.

If Robertson can move the ball inside, he can set hitters up outside. If he can let his pitches move where he wants in the strike zone, the lefty can also set a pitch on the edge of the zone that tempts hitters enough to misplay the ball, rather than completely miss.

"Command and control, back and forth and up and down, getting ahead, realizing the kind of game you have, those are things that are going to make you good," Knapp said. "If you add velocity on top of all those things, you'll be really good."

Robertson has never been a big ground-ball pitcher. His highest ratio of ground balls to fly balls was 1.08 in 2005, but it has fallen in the three years since. He has had more fly balls than grounders in each of the past two seasons, good for a 0.87 ratio in '07 and 0.88 in '08.

While his batting average against on ground balls has been higher over the past two seasons, according to baseball-reference.com, his slugging percentage against on fly balls soared from .609 in 2007 to .719 in '08.

Robertson can be successful without the same velocity, Knapp said. But he has to adjust. Knapp saw strides towards that Saturday.

"I think there are plenty of left-handed pitchers in the big leagues with the same stuff that he has," Knapp said.