The biggest piece of that youth movement, second baseman Dustin Ackley, is about to make his major league debut.
Peguero's lucky-bounce, two-run single in the seventh inning put Seattle in front, Halman added a solo homer in the eighth, and Erik Bedard threw seven shutout innings in the Mariners 3-1 win over the Los Angeles Angels.
Seattle salvaged the final game of the series with the best team in baseball, the Philadelphia Phillies, headed to town for a three-game interleague series this weekend.
And when the Phillies get here, Ackley will be waiting. The Mariners announced after the game their prized, sweet-swinging infielder would be recalled from Triple-A Tacoma on Thursday and Luis Rodriguez would be optioned.
"We just felt it was time," Seattle general manager Jack Zduriencik said. "We had talked that at some point in June this would probably be when he would be ready and in the discussions with the coaches down there we feel this is the time. He's been swinging the bat well.
"So, here it is."
It's the move that's been anticipated by Mariners fans since the decision in spring training to send Ackley to the minors for more grooming. He'll join a lineup that's gotten progressively younger as the season has progressed, yet the Mariners enter the weekend against the Phillies a game over .500 and just one game back of Texas in the AL West.
Peguero's been a big piece of that youth and got his second fortunate break this season against the Angels to give Seattle the lead.
With two outs in the seventh, Peguero's grounder up the middle ricocheted off second base, over the head of Los Angeles shortstop Erick Aybar and into center field to score a pair. Seattle loaded the bases in the seventh on Angels starter Ervin Santana (3-7) thanks to a double from Chone Figgins and intentional walks to Ichiro Suzuki and Justin Smoak. On the seventh pitch, Peguero dribbled his grounder back up the middle.
Aybar was in position to make the play, but dropped his arms to his side in frustration as the ball hopped into center field to score Figgins and Suzuki.
The runs snapped a streak of 19 straight scoreless innings by the Mariners after they were shut out Tuesday night and made a winner out of Bedard, who gave up just three hits in seven innings.
Halman, a defensive replacement in the top of the eighth, hit a liner off reliever Rich Thompson out to deep center field in the bottom of the inning to give Seattle a little cushion.
"I hit it pretty good. I wasn't sure it was going out at first, but I was going hard out of the box," Halman said. "I'm happy it did."
It was the second time this season Seattle, and Peguero specifically, got an awkward, lucky break to beat the Angels. On May 19, Peguero's ninth-inning flyball got lost in the sun by Torii Hunter, allowing Jack Cust to score the winning run in a 2-1 victory.
"This dude has a lot of luck," Hunter said of Peguero. "We were here last time, the sun ball and now the second base bag. I need to take him to the casino. I think we could win.
Bedard (4-4) won his third straight decision, but it was his first win since May 25 at Minnesota. And he was at his best, giving up a pair of singles in the second inning to Vernon Wells and Peter Bourjos and a double in the fifth to Bourjos. Both times, the Angels left runners stranded at third base.
Bedard struck out five and walked none, getting to a three-ball count on just three of the 24 batters he faced. David Pauley gave up just his third earned run since April 18 working the eighth, but was the bridge to Brandon League, who got his AL-leading 19th save pitching the ninth.
Bedard also got a little defensive help early that kept the Angels off the board with Carp keeping the game scoreless in the second inning when he jumped at the wall and robbed Mark Trumbo of -- at the very least -- a double and possibly a home run. Carp's leaping grab came where the left-field wall jumps up about 10 feet and it was difficult to determine if Trumbo's shot would have cleared the fence.
Either way, it was a big play as Wells could have scored if not for Carp's grab. Franklin Gutierrez also made a diving catch on Aybar leading off the fifth inning.
"We made some really good defensive plays," Bedard said. "That's the only reason we're there talking about a win right now. You've got to give it to the defense today."
Suzuki stole the 400th base of his career in the first inning with a steal of third. He's the fourth active player in baseball with 400 steals, joining Juan Pierre, Carl Crawford and Omar Vizquel. ... The Angels released LHP Scott Kazmir on Wednesday after the former two-time All-Star continued to struggle on a rehab assignment at Triple-A Salt Lake. Kazmir was battered for six runs in 1 2/3 innings Tuesday night in his fifth rehab start. ... Suzuki had two doubles, his fifth straight multihit game.