So what exactly is Felix Doubront? What are we to glean from his first 10 starts of 2012?

Try this on for size: At his current rate, he would become the second 24-year-old, left-handed starter since 1901 to strike out at least a batter an inning while qualifying for the ERA title. The first was none other than Sandy Koufax, who did the trick for the Brooklyn Dodgers in 1960, when he tossed 175 innings and struck out 10.1 batters per nine innings.

Obviously, that is not to suggest that Doubront -- who was, by and large, outstanding against the Tigers in Monday’s 7-4 Red Sox victory -- is the logical successor to Koufax. Indeed, a slightly broader search suggests that membership in the club of young strikeout-per-inning lefties is no guarantee of career greatness. Even so, if Doubront continues at his current pace, he would belong to a special category of promising pitchers.

In the last 111 years, just 12 left-handed pitchers age 24 and younger have logged at least 140 innings while striking out a batter per inning. If Doubront hits that innings tally while maintaining his strikeout-an-inning stuff, he would become just the 13th member of an elite club, joining:

-- Koufax (who did it two times);
-- Reigning NL Cy Young winner Clayton Kershaw (three times);
-- Two-time Cy Young Award winner Johan Santana (once);
-- “Sudden” Sam McDowell (three times), a six-time All-Star;
-- Scott Kazmir (three times), a two-time All-Star who helped put the Rays on the map;
-- Herb Score (two times), whose amazing career start was derailed by injuries;
-- Sid Fernandez (once), who for several years was among the most unhittable pitchers in the majors;
-- Frank Tanana (once), who went on to win 240 games;
-- Balor Moore (once), the first draftee in Expos history whose career stalled in the gate due to injuries and command woes;
-- Tom Hall (once), who did it as a young reliever;
-- and a pair of pitchers -- Oliver Perez (once) and Rick Ankiel (once) -- whose careers were undone by command woes.

Here’s another comparison, a bit closer to Doubront: Jon Lester had his breakout season at age 24 in 2008. Through 10 starts, he had a 2-2 record, 3.95 ERA, 5.2 strikeouts per nine innings and 4.6 walks per nine. (His 11th start was his no-hitter against the Royals.) Doubront has a 5-2 record, 3.86 ERA, 9.5 strikeouts and 3.9 walks per nine.

In other words, the opening act of Doubront’s career as a fixed member of a big league rotation has been little short of tremendous. In 10 starts, he has shown strikeout-an-inning stuff, with 59 whiffs in 56 innings. On Monday, he struck out six Tigers in six innings, including a pair of punchouts of Miguel Cabrera, one in which he blew three fastballs past the overmatched slugger.

“I respect him, I respect him. I know he’s a good hitter. I think the principle is I didn’t show any fear,” Doubront said. “Just throw the ball and make him swing the bat, that’s very important, and throw the ball with conviction. That’s the key to get out a good hitter like him and Prince Fielder.”

To this point in the 2012 season, Doubront has exceeded any possible expectations the Red Sox might have had for him when they committed to him as one of the members of their rotation. His pitch mix -- a 91-95 mph fastball and a full complement of three swing-and-miss secondary pitches (changeup, cutter, curve) -- has allowed the left-hander to put the Sox in a consistent position to win.

He’s allowed three or fewer earned runs in eight of his 10 starts, with Monday marking his sixth quality start. In his career as a big league starter, which now spans 13 outings, he’s never permitted more than five earned runs.

His mound presence is commanding. In stature and delivery, he bears some resemblance to a standout Yankees starter.

Sox pitching coach Bob McClure opined that Doubront reminded him of “maybe [Andy] Pettitte a little bit. I think Felix has more of an arsenal of different pitches. But delivery-wise, kind of, [and with his] intensity and competitiveness and good feel. He has above-average feel for a 24-year-old. So, he has a lot of good things going for him, so just let him grow.”

To this point, Doubront has overpowered lineups in a fashion that has made it difficult to work deep into games. He’s recorded just one out in the seventh inning, although in some ways that is a reflection of the quality of his stuff rather than a shortcoming.

“You have to understand that his stuff is tough to hit. He gets ahead in the count, and then they foul a couple of balls off, so there’s pitches that are going to be thrown,” Sox manager Bobby Valentine said. “He doesn’t like to throw it necessarily down the middle when he’s ahead. We’ve been talking about that one-ball, two-strike count, and he had about another seven of them today. That’s pretty good.

“We like him to get one-pitch outs, but it’s tough. His ball moves so much. They get paralyzed, often, on that first pitch. It takes some time for the hitter to figure out what it is they’re swinging at.”

In time, perhaps, Doubront will find a few opportunities in games to get early count contact rather than getting to one 2-2 count after another. But for now, the Red Sox suggest that it would be a mistake to try to change a mix that has been successful.

“When you’re that age you don’t want to start [messing] with that stuff,” McClure said. “When they’re that age, the more you mess with them you’ve got a chance of messing them up. If he goes six or seven innings and ends up with a high-two or three ERA then that’s pretty darn good for a 24-year-old kid in the American League East.

“Just from my experience, you just don’t mess with it. You let them grow into it confidently. He is convicted, he is aggressive. I don’t want to start having him back off. He has given us a chance to win almost every time he has pitched, so we will just kind of leave it.”

Lester can identify with the fine line that Doubront is navigating between swing-and-miss stuff and pitch efficiency. It is a battle that Lester faced early in this career, particularly in his rookie year of 2006, and that the Red Sox’ Opening Day starter says that he must still endure.

Lester suggests that experience is a great teacher in that regard, that the difference between a six-inning outing and a seven- or eight-inning performance is just a handful of pitches a game. To this point, however, he sees no reason to try to change the way that Doubront is operating, given the way in which he is, for the most part, carving up opposing lineups.

“I’ve heard some stuff where people will be like, ‘He had an OK start. He’s doing OK.’ I think he’s done great,” Lester said. “The innings will come. That’s just experience.  His stuff is there to punch guys out, and also have quick innings, which he’ll figure out. We all go through it. We all do it. It’s just a matter of being able to recognize it.

“He’s doing a great job, I think. He doesn’t look rattled, gets on the mound, throws the ball, competes, and that’s all you can ask of a guy who’s in the rotation for the first time,” he added. “I’ll take six innings from him 100 pitches at a time. With his stuff, just let him pitch.”

The Red Sox will do just that. At the start of spring training, Doubront was an oft-overlooked candidate for the rotation. Two months into the year, he has become a staple. He is young, is left-handed, has a powerful pitcher’s build and has shown a very advanced pitch mix, a combination that has served as a formula for tremendous early season success.

Whether he can sustain such performance -- and whether he can remain healthy over the course of a big league season -- remains to be seen, but for now Doubront’s emergence has shown the potential to change the shape of the Red Sox rotation not only now but for seasons to come.