CLEARWATER, Fla. - The words J.A. Happ had waited 3 years to hear were spoken in a hushed tone, shrouded by the consuming silence of the end of a season. Rich Dubee pulled up an office chair in the visitors' clubhouse at Yankee Stadium and motioned for Happ to sit across from him. As dejected teammates and staff shuffled around them, the pitching coach and the young lefthander talked.

"I told him that it was my opinion, and there would be other opinions, that would have to weigh in," Dubee said yesterday, "but it was my opinion that he came in to spring training with a job in our rotation."

Four months later, as Happ prepares to open the Phillies' spring schedule with a start against Florida State tonight, those words have proved true. Fresh off a rookie campaign in which he went 12-4 with a 2.93 ERA, pitching three complete games and finishing second in the NL Rookie of the Year voting by the Baseball Writers Association of America, Happ is entrenched as a member of a big-league rotation for the first time in his young career.

But you can forgive him for not showing up to spring training with a bottle of Cristal in his right hand and a major league entourage to his left. After a postseason in which he made just one start and six relief appearances, and an offseason in which he listened to various "experts" attribute much of his success to luck, the 27-year-old Happ is well aware that he has plenty left to prove.

"I'm not going to take too much out of it," Happ said. "I mean, it's a little bit disrespectful to assume everything was luck last year. I think it's very hard to have a full year in the big leagues and be lucky. But I guess it's on me to show."

To understand the skepticism about the sparkling numbers that Happ produced in his rookie season, you must first understand the way in which the statistical evaluation of pitchers has changed, from basic metrics such as wins and ERA, to advanced formulas like FIP (Fielding Independent Pitching) and xFIP.

The basic premise of sabermetrics - the analysis of baseball through objective evidence, as coined by well-known researcher and current Red Sox executive Bill James - is that a true measure of a player's performance lies in the aspects of the game over which he has the most independent control. Just like a pitcher's control over his win total is dependent on factors such as the amount of runs his offense scores, his control over his ERA is dependent on factors such as the defense that plays behind him.

For this reason, many experts put more stock in a pitcher's FIP, and xFIP, which measure his performance based on three variables that he controls: strikeouts, walks and home runs allowed. Those three rates are then plugged into a formula that results in an ERA-like number, which, according to the well-respected publication "Baseball Prospectus," helps quantify "how well a pitcher pitched, regardless of how well his fielders fielded." A variation of FIP, xFIP's home run component is measured against flyball rate.

The acceptance of such statistics gained considerable momentum this offseason, when AL Cy Young winner Zack Greinke said he puts more emphasis on sabermetric principles than measures such as wins and ERA.

"That's pretty much how I pitch," Greinke said, according to the New York Times, "to try to keep my FIP as low as possible."

Which brings us to Happ, who finished 2009 with a striking disparity between his ERA (2.93) and his FIP (4.33) and xFIP (4.49). In other words, he managed to rank eighth in the NL in ERA, despite a strikeout rate (6.45 per nine innings), walk rate (3.0 walks per nine innings) and home run rate (1.1 HR/9) that ranked right around the league average.

Happ also held hitters to a .158 batting average with runners in scoring position, resulting in his stranding 85.7 percent of his baserunners, which statistical research suggests will be difficult to maintain.

All of these factors, combined with his reliance on a fastball that averaged around 90 mph last season, led many experts to believe that Happ's stellar ERA was more a product of luck than skill.

"Happ's ERA should be somewhere in the mid-4s, and if that was the case, no one would be talking about him as a lock for rookie of the year," wrote ESPN analyst Keith Law, a former member of the Blue Jays' front office, after seeing Happ pitch last September.

Later, in the offseason, Law wrote that Happ's season was "a raging fluke driven by an unsustainable performance with men in scoring position that was about luck, not skill."

As one might expect, neither Happ nor the coaches who know him best subscribe to such beliefs. And in doing so, they point to a number of factors that concrete numbers are unable to quantify, from pitch sequence and deception to sheer intelligence and will.

"He's a very sharp kid, very intelligent," Dubee said, "but he's also got a nice demeanor on the mound. He's very poised, very aware of situations, very aware of the game itself and how to control himself."

Happ's feel for situational pitching is one thing that might get lost in the numbers. For example, FIP is heavily dependent on a pitcher's walk rate, but it assigns the same value to all walks - whether it is an "unintentional" intentional walk issued to the No. 8 hitter with the pitcher on deck, or if it is a walk with the bases loaded.

While Happ averaged one walk every 12.2 plate appearances, he averaged one walk every 25.6 appearances against hitters who led off an inning. Of his 56 total walks, 25 came with two out, compared with 13 with no out. Greinke, who led the majors in FIP, walked the leadoff man once every 17.9 plate appearances, and walked batters at a similar rate regardless of the number of outs in an inning.

"You'd like everybody to cut down on walks," Dubee said, "but you have to look at the walks . . . Are they just some real bad deliveries or are they walks where you are pitching around a guy in a situation? Some walks are justifiable. Some aren't. He's got intelligence. He's got awareness of lineups, hitters, situations. Those all play into the game."

Another hard-to-quantify aspect of Happ's game is his deception. At 6-6, he has long legs and a long wingspan and a delivery in which the ball remains largely hidden until he releases it. Because hitters pick up Happ's release point late, the ball appears to be traveling faster than a radar gun might indicate. In fact, according to Phillies minor leaguer Michael Schwimer, who has conducted in-depth studies on release points and velocity, the "perceived velocity" on Happ's fastball is between 94 and 96 mph, even when a radar gun clocks it between 88 and 92.

"The less time you show [a hitter] the ball, the faster it appears," Schwimer wrote last summer for the Web site PhuturePhillies.com. (Schwimer politely declined to be interviewed about his studies and instead referred the Daily News to his blog entry.)

Tim Stoddard, a former major league pitcher who served as Happ's pitching coach at Northwestern, pointed to Happ's whiplike arm speed and late movement on his fastball.

"He creates a really good angle," Stoddard said. "He's throwing the ball downhill every time. He's got good arm speed, and that's what [hitters are] reading."

The player Happ most favorably compares to is Padres righthander Chris Young, a 6-10 former basketball player at Princeton who posted a 3.46 ERA in 31 starts for the Padres in 2006 at the age of 27. Like Happ, his ERA that season was far superior to what his sabermetric stats suggested it "should" have been. Young posted a 4.60 FIP and 4.62 xFIP that year while holding hitters to a .176 average with runners in scoring position and stranding 80.7 percent of his baserunners. He also held hitters to a .237 average on balls in play, a statistic that sabermetric research suggests is more a product of luck than skill.

Nevertheless, Young posted an ERA of 3.12 in 2007 and 3.96 in 2008 before shoulder problems derailed his 2009 season.

"As far as deception, they are very similar," Dubee said.

Regardless of his success - actual or relative - Happ spent much of the offseason training at Northwestern, working on his secondary pitches, and occasionally throwing live batting practice to the Wildcats' baseball team.

"I took like 10 days off, and then got back in the weight room and tried to maintain flexibility and gain strength," Happ said. "I don't want to say I'm a slow starter, but I still don't feel like I can come out slow and not ready. I need to get ready just like everybody else, and I need to prove that I am ready."

In fact, it was a message that Happ imparted to the collegiate athletes during a weightlifting session that impressed Stoddard and invoked images of that post-World Series chat between the young lefty and his big-league pitching coach.

"It gets easier and easier to work out," Happ told the Wildcats, "because I know if I'm not working out, somebody is going to take my job, or the opposition is."

For more Phillies coverage and opinion, read David Murphy's blog, High Cheese, at http://go.philly.com/highcheese.