With Rivera in their lineup in 2008, the Angels were 47-19 for a sizzling .712 winning percentage. When their muscular outfielder took a seat on the pine, the club was 53-43, a .552 winning percentage.
As humble as he is powerful, Rivera accepted no credit for any of this. He was visibly surprised when these numbers were presented to him.
"Hmmm," he said, grinning. "Just lucky, I guess."
The Angels brought back the 30-year-old Venezuelan with a three-year contract after he'd filed for free agency with the expressed intention of playing on a regular basis -- somewhere.
"We know what Juan is capable of doing," manager Mike Scioscia said. "I'm looking forward to seeing what he can give us this year."
Rivera is expected to spend most of the 2009 season in left field with Garret Anderson almost certain to depart as a free agent.
The Angels were 25-10 with Rivera in left in '08. They were 11-4 when he spelled Vladimir Guerrero in right and 11-5 when Rivera was the designated hitter.
His numbers weren't overly impressive -- .246 average, 12 homers, 45 RBIs -- but Rivera found his groove after the All-Star break with nine homers and 34 RBIs in 170 at-bats, hitting .253.
In a loaded Angels outfield, it was his first extended opportunity since he broke his left tibia three days before Christmas in 2006 playing winter ball in his native Venezuela. The baserunning misadventure came on the heels of a breakout season.
Rivera had been a force in '06, hitting .310 with 23 homers and 85 RBIs in 124 games. He gave Guerrero a mashing partner and appeared on the threshold of settling in as a centerpiece in Scioscia's lineup.
Rivera leaves no doubt that he can recapture that level of production with steady employment.
"I know I can hit," Rivera said late last year. "It was just a matter of staying patient and waiting for my opportunity."
After spending the first eight years of his professional career with the Yankees, watching high-priced talent play while he waited for his time to arrive, Rivera flourished with his first steady job in the game.
It came in 2004 in Montreal -- thanks, in part, to Guerrero, who departed Canada for the Angels' free-agent riches after the '03 season. Needing a bat to replace their main man, the Expos sent pitcher Javier Vazquez to the Yanks for Rivera and two other players.
Rivera hit .307 in '04 with 12 homers and 49 RBIs in 391 at-bats.
That winter, Rivera was packing his bags again. He would be joining Guerrero along with Maicer Izturis as the Angels shipped Jose Guillen to Washington, the Expos having become the Nationals.
Rivera hit .271 in '05, showing his power with 15 homers and 59 RBIs in 350 at-bats. That set the stage for his '06 breakout -- followed by the break in his lower left leg.
One reason the Angels aren't overly concerned about a lineup loaded with right-handed bats is that most of their hitters -- Rivera included -- have handled righties just as effectively as lefties.
Rivera is a .284 career hitter. His lifetime slugging percentage is slightly higher against southpaws (.808 to .794), but his on-base mark is better against righties (.336 to .322).
"Sometimes I see the ball better against right-handed pitchers, for some reason," Rivera said. "It really doesn't matter to me who I face, as long as I'm in the lineup somewhere."
Fully healed and optimistic, Rivera heads into 2009 hoping to make up for lost time.
"I'm still young," he said. "I have a lot of baseball left in me. I love the game. All I've ever wanted was a chance to play and win."
The Angels like Rivera enough to have invested in him for three years.
A 225-pound good-luck charm, after all, should not be taken lightly.
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.