BALTIMORE — Ken Griffey Jr. was back in the Seattle Mariners’ clubhouse Tuesday, which meant the usual heckling, cackling and general clubhouse mayhem. Spotting Ichiro Suzuki with his back turned, Griffey wrapped him in his arms and tickled him until Suzuki showed proper deference.

“You are not the man!” Suzuki wailed, until finally giving in, to raucous laughter all around.

It was only a year ago, in the same Camden Yards clubhouse, that the Mariners called a team meeting to support Griffey after a report that he had been sleeping by his locker during a game. Griffey soon retired — he is now a team consultant — and Seattle lurched to 101 losses.

The Mariners are still in last place, and their offense is feeble. But optimism reigns, largely because of Michael Pineda, the hulking 22-year-old strike-thrower who faced the Baltimore Orioles on Tuesday.

The Mariners believe they could contend soon with Pineda and Felix Hernandez, last season’s American League Cy Young Award winner, anchoring their rotation. The presence of Pineda as a second potential ace is especially enticing because Hernandez is signed through 2014, making Seattle unlikely to trade him.

“You start putting the pieces together, and you look at the two pitchers at the top of the rotation,” general manager Jack Zduriencik said. “We’re going to have a lot of money coming off the books this year. It’s going to be a very, very interesting ride for us as we move forward. With my background in scouting, I know it’s going to take time. But I’m excited, and it could happen quickly.”

With rookie hitters making little impact this season, Pineda has been a revelation on the mound. He is 4-2 with a 2.84 earned run average in seven starts, with more strikeouts than innings. Dig a little deeper and you see what really sets him apart.

According to FanGraphs, Pineda is the hardest-throwing starting pitcher in the majors, with a fastball that averages 96 mph. He has also thrown a first-pitch strike to 73.7 percent of his hitters, the best figure in the game. He fired a first-pitch strike to his first 12 hitters Tuesday, and 21 of 26 overall.

“He’s a very gifted young man,” said the Orioles’ Luke Scott, who struck out in his first two at-bats. “Live fastball. He threw some good sliders to me, backdoor, an inch off the plate away — you can’t do anything with that pitch. He’s got a great arm; he hid the ball well. When you’ve got that kind of stuff and you’re pounding the zone, you get guys in swing mode.”

That was Scott’s approach with two outs and one on in the sixth inning. Pineda had allowed just one run, but Scott singled on a first-pitch fastball, and two more hits brought in two runs. Pineda finished the inning, striking out six with one walk in a no-decision. The scoreboard clocked three of his 100 pitches at 98 mph.

Pineda’s willingness to challenge hitters suggests supreme confidence in his stuff — not surprising, considering how hard he throws. He is 6 feet 7 inches and 260 pounds, but his mind-set mirrors that of a smaller pitcher, Pedro Martinez, whom he idolized growing up in the Dominican Republic.

“Pedro is a little guy, but on the mound, he’s a big guy,” Pineda said. “He’s never scared of the hitter. He throws the ball, focused. I like this a lot. He’s never scared — never.”

In the Mariners’ clubhouse, Hernandez, at 25, is more peer than icon, and a different style of pitcher. Hernandez, who is from Venezuela, has a more refined changeup and more sink on his fastball, producing more ground balls. Pineda works up in the zone; only Colby Lewis of Texas generates a higher percentage of fly balls among AL pitchers.

Still, Pineda regularly consults Hernandez for advice, mostly on hitters, and Hernandez is happy to help. With his long-term commitment to the Mariners, he is eager to nurture Pineda’s development.

Pineda signed with Seattle at age 16, in 2005, and he played his first two seasons for their Dominican Summer League team. His first U.S. pitching coach, at Class A Appleton (Wis.) in 2008, was Jaime Navarro, who is now Seattle’s bullpen coach.

Navarro coached Pineda at two other minor league levels, and he said Pineda was like a son. They lived together last season at Class AAA Tacoma and again this season in the Seattle suburbs.

Navarro, who is from Puerto Rico, said he speaks to Pineda in English to help him learn the language. Pineda got his driver’s license last month, and Navarro will toss him the keys to his Oldsmobile so Pineda can drive them to Safeco Field. He has taken Pineda shopping and bought him suits for road trips.

Navarro also nurtured Pineda through an elbow injury in 2009, detecting a flaw in his mechanics before the problem became too severe. Pineda missed most of that summer but returned strong, throwing harder than before.

“You don’t have to say a lot of things to that guy; he’s got a pretty good arm,” Hernandez said. “I’ve got six years here, I know the guys in the league, I know what I have to do. He’s learning, but he’s going to be one of the best.”