There hasn’t ever been much mystery to what Brad Penny does on a mound. That remained the case in the right-hander’s Red Sox debut.

In his first inning with his new club, Penny unleashed 15 pitches. Of those, 14 were fastballs. The hard-thrower rarely veered from that approach, sticking with his bread-and-butter pitch for 65 of his 86 (75.6 percent) offerings against the Angels.

His velocity, which started in the high-80s, built as the game progressed. Nine of his pitches punched in at 95 mph. That number has some significance for a pitcher who signed with the Sox in hopes of returning to strength after a struggle with shoulder tendonitis in 2008.

“I didn't have the velocity I have now last year at all,” Penny said during spring training. “One day I’d be 92, the next day I’d be 86. I don't think there was a game where I touched 95. ”

Now, there are signs that he is doing just that. As such, it’s hard to fault Penny – who makes his second start as a Red Sox on Friday against the Orioles – for returning to a fastball-heavy formula that has worked over his career. There has been no need for subtlety thanks to one of the most powerful heaters in the game.

According to the “Bill James Handbook,” Penny led National League starters in average fastball velocity in 2006 (93.9 mph) and 2007 (93.4), a two-year span in which he emerged as one of the best starters in the N.L. In ’06, he registered 95 or higher on a radar gun 817 times. No one else in the N.L. came within 200 of that number of 95+ mph fastballs.

Penny also features a curveball and changeup and occasional splitter, but those are all secondary pitches in the most literal sense. He subscribes to the theory that a four-seam fastball is, in fact, several different pitches, depending on where it’s thrown.

To Penny, the fastball up-and-in and a heater down-and-away are two different kinds of pitches, and so if he is commanding, Penny feels comfortable attacking just with a fastball.

“If I’m locating in and out, up and down,” said Penny, “usually I can get through two or three innings with just the fastball.

“You can use the four-seam fastball as four different pitches. Just keep them guessing,” he added. “A lot of guys who are fastball hitters, that’s fine as long as I locate. If you’re looking for a pitch and I locate that pitch, it’s still effective.”

When healthy, Penny would appear to be the prototypical power pitcher, someone who is incredibly aggressive in challenging opposing hitters with hard stuff. In approach, that has certainly been the case. In outcome, however, it’s a different story.

Penny has never finished in the top 10 in his league in either strikeouts or strikeouts per nine innings. He has struck out as many as 10 batters only once since the start of the 2005 season. Last Saturday, he elicited just two swings and misses in his entire outing.

That is, the pitcher claims, by design. In that sense, Penny is a fairly unusual pitcher.

Other pitchers who are as fastball reliant as he is typically use the pitch to get either a lot of groundballs (sinkerballers such as Derek Lowe and Aaron Cook come to mind) or swings and misses (the Josh Becketts of the world). Penny, however, attacks with a fastball that is hard but that tends to result in fly balls. 

“I pound the zone. If I start trying to strike people out, I’ll be at 110 pitches in the fifth inning,” said Penny. “I have my games where I’ll strike out people. But in my career, I haven’t been a strikeout pitcher. I’ve tried to pitch to contact.

“For the most part, when you’re younger, of course you’d try to strike people out,” he continued. “But what made me turn, you realize how many foul balls or deep counts you’re getting in. You’d go 0-2 and all of a sudden you’re 3-2. You’ll get deeper in the game if you pitch to contact.”

If he is able to execute that game plan in the same fashion that he did from 2005-2007, when his 3.73 ERA ranked 13th in baseball, then the Sox will have a formidable presence at the back of the rotation. If he can come close to that form this year, the Sox could enjoy tremendous return on their one-year, $5 million investment.

That Penny was slotted in as the fifth starter to open the season speaks volumes about the strength of the Sox, and a reason why anxiety in New England seems premature in the face of the team’s slow start.

It was just a year ago, after all, that Penny – coming off a season when he finished third in the N.L. Cy Young race – took the ball on Opening Day for the Dodgers and fired 6.2 shutout innings.

“We’re very deep. We have a lot of guys that could slip into any spot,” said Beckett, who has been reunited with Penny after the two pitched together with the Marlins earlier this decade. “Brad’s started Opening Day before. Brad’s been thought of as that guy.”

Now, he is just “a guy,” a power pitcher who slips unassumingly onto a Red Sox staff that is loaded with precisely those sorts of arms. For Penny, that place is a welcome one.

“A lot of guys on this team deserve to be a No. 1 starter,” said Penny. “The reason I came here was because of, one, the shoulder program, and two, they have a chance to win the World Series. That’s what you play for.”