This offseason, the Red Sox did not re-sign Bay -- the power-hitting righty bat who has averaged 30 homers and 99 RBIs since 2004, and whose uppercut trajectory was tailor-made for the Green Monster at Fenway Park. Instead, Boston acquired Cameron -- an All-Star in his own right, but one who is older and whose 22-homer, 69-RBI average the past six years pales in comparison.
So, because of that, questions of whether the Red Sox can hit enough to get past the reigning World Series champion Yankees have raged on, especially when you consider David Ortiz's declining numbers the past two years.
But there is one certainty in this outfield equation: The Red Sox will defend as well -- or better -- than anybody in the league.
"I know a lot of emphasis, a lot of talk, has been on our offense last year and how to fix our offense," Red Sox general manager Theo Epstein said recently. "Lost in that mix is that our run prevention needs some improvement, as well. We were one of the worst defensive clubs in baseball last year, and we think Mike is a very important piece towards fixing that."
Based on Ultimate Zone Rating, the Red Sox ranked seventh in the American League defensively at -16.3. The outfield, in particular, was tied for 11th in the league at -25.6.
But in comes Cameron, the three-time Gold Glove Award-winning center fielder who plays a lot younger than his age, 37, would indicate.
Cameron joins Jacoby Ellsbury and J.D. Drew in an outfield that features three players who each have the ability to play more-than-capable center field if needed.
Ellsbury himself is a center fielder, but manager Terry Francona told Ellsbury shortly before Christmas that he was going to go with Cameron in center and put him in left, which is a vast upgrade over Bay, and even more so when compared to when Manny Ramirez patrolled the area in front of the Monster.
"I think I've played Gold Glove-caliber center field pretty much my whole career," Cameron said recently. "I still feel that I'm able to move around pretty good. I played probably one of the better center fields [in '09] that I've played in a long time. I'm not knocking the other years that I played, because I try to play well every year. But it's part of who I am and part of being able to do the craft to the best of my ability to help the team defensively and definitely put a sense of confidence in the pitchers."
Cameron also has some pop, but he is a .250 hitter with a .340 on-base percentage and a .448 slugging percentage throughout his 15-year career. While with the Brewers last season, Cameron matched his career batting average, and it was actually an improvement over the .243 and .242 he hit the previous two years.
But Cameron, who mainly batted fifth, sixth and seventh during his two-year stint in Milwaukee, should be good for about 20 homers and 70 RBIs, if healthy.
"He's been one of the most consistent players in the game," Epstein said. "If you look, he's going to hit you his 20-25 home runs every year. He's going to play outstanding defense. He sees a lot of pitches at the plate. We think he's an underrated offensive player. He's a plus defender, a great guy in the clubhouse. He fits in really well with what we do here."
In Ellsbury, the Red Sox are set at the top of the order with a speedy lefty hitter who still has some tremendous upside.
From 2008 -- his first full season -- to '09, Ellsbury improved in almost every offensive category, from batting average (.301 last season) to on-base percentage (.355), RBIs (60), triples (10, which was tied for the AL lead), stolen bases (a league-leading 70), doubles (27) and hits (188) while playing in eight more games.
Defensively, a UZR of -18.6 ranked Ellsbury last among Major League center fielders who qualified last season. But UZR isn't a full measure of a player's defensive capabilities. The 26-year-old was still the fans' choice on MLB.com for Defensive Player of the Year, and he's played 80 of his 352 career games in left field, making the Green Monster a rather easy transition.
Besides, Ellsbury is still a center fielder playing a much less demanding position in left field.
"I think Jacoby's first-step quickness just really ... I think he'll be dynamic over there," Francona said recently. "We've seen Carl Crawford in Tampa for so many years. You've got a center fielder playing left field. That thought has intrigued us for a long time."
In Drew, the Red Sox have a guy with the skills of a center fielder, which is crucial at Fenway Park, which boasts one of the toughest right fields in the Major Leagues.
Offensively, the 34-year-old lefty hitter's numbers aren't eye-popping -- though the .279 batting average with 24 homers and 68 RBIs he put up in 2009 is solid -- but the Red Sox value his ability to get on base. Over the past two years, Drew has posted a combined on-base percentage of .399, a slugging percentage of .521 and an OPS of .920.
As reserves, the Red Sox will have newcomers Jeremy Hermida and Bill Hall, who's mostly been a shortstop and third baseman throughout his eight-year career, but has a significant amount of experience -- 174 games -- as an outfielder.
The wild card here is Hermida.
The 26-year-old lefty hitter rose through the Marlins' farm system quickly after being a first-round Draft pick in 2002. But he simply hasn't lived up to expectations. While playing at least 123 games each of the past three years, Hermida -- who has a solid arm but also a knack for getting lost on semi-routine fly balls -- has batted .267 while averaging 16 homers and 57 RBIs.
Boston is hoping that with a change of scenery, Hermida can rediscover the tools that made him one of the top prospects in baseball a short time ago. And if that happens, he could form a nice platoon with the righty-hitting Cameron.
But for now, Hermida is just taking things in stride.
"I'm just happy to be [with the Red Sox], to be honest with you," he said recently. "My role will be what it is. I'll come into Spring Training, and I'm going to work and prepare myself like an everyday guy. You never know what happens throughout the course of a season. So that's my job. And if it's being the fourth outfielder on Opening Day, I'm going to work at that and be the best I can at that."