Most World Series aren't won with flashy free-agent signings. They're won with prudent acquisitions that seem to fit the club just right.
This season we've already seen Zack Greinke, David Price, Jason Heyward and Ben Zobrist switch clubs. All four will probably be impacting pennant races in 2016.
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But they won't be the only new faces to do so. Last offseason, pitcher Chris Young and designated hitter Kendrys Morales signed deals with Kansas City that went largely unnoticed. Both played a key part in the Royals' title run.
So who might those stealth additions be this offseason? Which under-the-radar players appear to fit perfectly at their new clubs? Let's take a look:
Chris Young, OF, Red Sox
In one regard, Chris Young is a nice addition for the Red Sox simply because they stole him from the division-rival Yankees, who could use some right-handed pop. But the real value in Young's fit with the Red Sox is his skillset.
He terrorizes left-handed pitching -- which makes him a solid option to platoon with Jackie Bradley Jr. (in which case, Mookie Betts would play center). And he's been great at Fenway Park, hitting .344/.431/.623. It's easy to see why he's had so much success in Boston. One glance at Young's spray chart confrims his pull-happy tendencies, and he should pepper the Green Monster all season.
Young is capable of producing both off the bench and as a starter. If everything goes right, Young will be able to give the trio of Betts, Bradley and Rusney Castillo occasional breathers based on matchups. And if any of those three struggles or gets hurt, Young will slide right into the lineup.
Video: Duquette on Red Sox adding veteran outfielder Young
Tyler Flowers, C, Braves
Flowers is probably never going to post gaudy numbers, but his offense has improved over the past two seasons when he was given more playing time. His .240 average and .300 OBP aren't great, but for a defensive-minded backstop, that should be plenty.
Flowers' true value lies in his pitch-framing ability, which should be a major boost for a Braves club in rebuilding mode. Among the eight potential starting pitchers that could make Atlanta's Opening Day roster, none are older than 25.
Those young arms will receive a serious boost in their efforts to work the corners. Flowers got strikes called on 9.9 percent of pitches outside the zone last season -- the second highest rate among regular catchers. Plus, he's a perfect option to platoon with A.J. Pierzynski, with whom he split time with back in Chicago.
Video: Braves sign catcher Flowers to two-year deal
Wade Miley, SP, Mariners
The Mariners have seemingly reshaped their entire roster this offseason, and it wasn't easy for them to let go of Carson Smith. But they needed rotation depth.
Miley was a dreadful fit in Boston. He didn't get hit very hard, but he was a left-hander who gave up a decent chunk of fly balls -- and that never plays well at Fenway Park (or anywhere in the AL East, for that matter).
In 2015, Miley's 24.2 rate of hard contact was the eighth best among qualified starters. At Safeco Field, which routinely ranks among the worst hitter's parks, Miley's ability to limit hard contact should play nicely. Plus, he's pitched at least 32 times and racked up 190 innings in each of the past four seasons. With a young and unproven back end of the rotation in Seattle, stability is a welcome sight.
Video: PHI@BOS: Miley fans eight, goes the distance
Jedd Gyorko, IF, Cardinals
In all likelihood, the Cardinals are going to sign an outfielder capable of starting, which made Jon Jay expendable. So they shipped him to the Padres for Gyorko. It meant taking on a bit of salary, but the return could end up being worth it.
Gyorko had his share of ups and downs with the Padres, but never found consistency. Still, he regained his pop toward the end of the 2015 season, and his second-half slugging percentage was 113 points higher than the first half.
The main reason the Cardinals like Gyorko so much is his versatility. He figures to serve as a back up at second base, third base and shortstop, which gives the Cardinals some crucial roster flexibility. And he hits left-handed pitching well (.282/.358/.445 last season), which makes him a nice option for an occasional platoon with Kolten Wong at and as a late-inning pinch-hitter.
Video: Cardinals acquire Gyorko from Padres for Jay
Rich Hill, SP, A's
The Rich Hill experiment (one year, $6 million) could very easily fall flat in Oakland. After all, the A's are basing their investment off a mere four September starts.
Sure, Hill's numbers were brilliant in September (1.55 ERA, 0.66 WHIP, 7.2 K/BB). But the important question is: why? Were they an aberration or was there a reason for Hill's dominance? Well, Statcast™ tells us Hill's curveball had a spin rate of 2,705 rpms, putting him in the top 10 percent in baseball. The movement (an average of 9.58 inches) gave him a definitive out pitch.
There's also the matter of Hill's fit with Oakland. He's had a tendency to give up a high rate of fly balls, which plays nicely in the AL West -- and especially with the defense behind him. Oakland's infield defense posted a -35.6 ultimate zone rating last season, the worst in the American League. The outfield, on the other hand, posted a 2.3 UZR, above the league average.
Video: Athletics sign left-hander Hill to one-year deal
Shawn Kelley and Yusmeiro Petit, RPs, Nationals
Neither Kelley nor Petit is an option to close, but if the past few seasons have taught us anything, it's that bullpen depth is being valued more than ever before. The Nats have a conundrum with Drew Storen and Jonathan Papelbon remaining on the roster, despite the club's attempts to deal both of them. But general manager Mike Rizzo has done a nice job with the rest of the 'pen.
Kelley seemed to find a groove toward the end of last season, posting a 1.57 ERA and a 0.91 WHIP after struggling in April. Plus, he's equally adept against hitters from both sides of the plate.
Then there's Petit, whose role in San Francisco was to do just about everything. He started, he pitched long relief, and he pitched late in games. That type of versatile pitcher is the perfect fit for a club that hasn't yet resolved its plan for the rest of the 'pen -- and for a club with a pair of unproven arms at the back-end of its rotation.
AJ Cassavell is a reporter for MLB.com. Follow him on Twitter @ajcassavell.