Neither guy was a lock to make his team's rotation when Spring Training camp began. And looking back, neither was all that highly touted upon arrival to professional ball.

But at a time when pitchers seem to be hitting their stride at extraordinarily young ages, two of the best rookies in the big leagues thus far this season have been the Mariners' Michael Pineda and the Orioles' Zach Britton. And for their respective rebuilding teams, their presence offers plenty of hope.

We are but a month and a half into the 2011 season, and already this promising pair of self-made stars has provided early attention on the American League Rookie of the Year Award race, with the contending Rays' Jeremy Hellickson also firmly in the conversation.

Consider these numbers, entering Pineda's eighth start against the Twins on Monday and Britton's ninth outing against the Red Sox on Tuesday:

Pineda: 4-2, 2.84 ERA, 130 ERA+, 1.11 WHIP, .221 opponents' batting average.

Britton: 5-2, 2.42 ERA, 164 ERA+, 1.02 WHIP, .203 opponents' batting average.

While those stats are similar, the two young guns could not be more different stylistically -- and not just because Britton is a southpaw (and a former child actor, but more on that in a bit).

The 22-year-old Pineda, who was the AL Rookie of the Month in April, is your classic hard thrower and much more of a fly-ball pitcher. Fangraphs.com has him throwing his fastball 61.8 percent of the time and hitting an average velocity of 96 mph. He's throwing his 85-mph slider 31 percent of the time. It's a robust repertoire that Pineda controls remarkably well, as evidenced by his 73.7 first-pitch-strike percentage.

"I haven't seen that often," said Mariners pitching coach Carl Willis, the man who groomed CC Sabathia, "a guy that not only has his poise but also the ability to command and control the baseball with that velocity."

It would seem fair to compare Pineda, who is listed at 6-foot-7 and 260 pounds, to Sabathia because of their similarly big body types and power arsenals.

But whereas Sabathia was a seemingly can't-miss first-round Draft selection, Pineda was a project hauled in on a hunch. He was 17 and had made the conversion from the infield less than a year before Seattle signed him out of the Dominican Republic for $35,000 in December 2005, and nobody could have projected that both his body and his weapons would develop to the level they are at today.

"He really kind of grew into this," Willis said. "All of a sudden, he grew in height and he filled out. That athletic ability, he had allowed him to learn a pitching delivery. You look at a guy who is 22 years old with long arms and long legs, yet his ability to repeat his delivery and how easily he gets that delivery speaks to how athletic he is."

Pair Pineda with Felix Hernandez, as the Mariners have, and you have a dominant one-two punch in the rotation that could give this club the building blocks of a contender, if only Seattle could get the bats going to back them up.

"It's a good situation," Willis said. "It's great to have Felix here with [Pineda], because they talk a lot about how he approaches each day and how he works and prepares."

Pineda had told Willis and manager Eric Wedge that he was going to win them over and secure a rotation spot in Spring Training, and he did just that.

Britton, on the other hand, saw his lights-out spring camp go all for naught, as the O's optioned him to Triple-A Norfolk toward the end of camp. But an injury to Brian Matusz opened up an opportunity, and the 23-year-old Britton has seized it in dazzling fashion.

"Everybody told me that if you keep the ball down, you'll be fine," Britton said. "Spring Training meant a lot to me, and I took that confidence into the season."

Britton keeps the ball down with the kind of hard sinker you rarely see from a lefty. He's used it to post a ground-ball percentage of 54.4 that ranks among the best in the big leagues.

"It's a different presentation than what you [normally] see from a left-handed pitcher," Orioles manager Buck Showalter said. "You see left-handers who will throw a sinker, but not at the type of velocity Zach does. It's a different look."

Britton wasn't sure what kind of a look he'd get in the 2006 Draft. He was an all-state outfielder in high school and didn't necessarily know pitching would be his path to the big leagues, but the Orioles believed in him enough to make him a third-round pick. It wasn't until he developed his sinker by accident (he was working on a cutter with coach Calvin Maduro and stumbled upon the pitch that dives away from right-handed batters) that he emerged as a prized prospect.

Thanks to that pitch, Britton is an emerging young star. And he's already found the big leagues to be a quicker ticket to fame than his all-too-brief acting career.

A young Britton actually had a couple lines in the 2000 family comedy "Perfect Game," starring Patrick Duffy and Ed Asner.

"Me and my brothers had done some modeling when we were younger," Britton said, "and it just so happened they were filming this movie near where we lived, and they asked us to be in it. I look back on it now and say, 'This is a horrible movie.'"

The movie is about a Little League team that learns the value of teamwork, but the acting experience taught Britton something else.

"I thought you just show up on the set and read some lines," he said. "But it takes a lot of time to be an actor. I'd rather stick to baseball."

It's safe to say sticking to baseball has worked out pretty well for both Britton and Pineda.