The franchise has several hurlers who fit the bill, but the answer depends on your definition of an ace.
In the estimation of most fans, an ace is a go-to starter, a guy with killer stuff, a psyche strong enough to pitch through pressure situations and the stamina to give his team a quality start every time he takes the mound.
Your ace is the big-money, ice-water-in-his-veins guy your manager throws out there to end losing streaks, to win games you absolutely have to win.
Every pitcher — every player, even — experiences ups and downs on the field, but even during your ace's "downs," he should still be pretty solid. During his "ups," he should be nearly unhittable.
Of the Red Sox' options, Josh Beckett has the resume that most closely fits the ace's job description and he's the most established of the possibilities heading into spring training. The brash, 29-year-old Texan has led the squad in wins in three of his four seasons in Boston, going a combined 65-34 with a 4.05 ERA and 723 strikeouts in 792 innings.
Just as importantly, Beckett has simply filthy stuff when he's on. His fastball will hit the mid- to high-90s when he's rearing back and firing, and his breaking stuff is capable of rocking batters to sleep, especially when seen in contrast to his heat.
Beckett, too, wins when it matters. Before joining the Red Sox prior to the 2006 season, he'd already established a track record with the Marlins as a dominator in the postseason. He was the World Series MVP in 2003 as Florida beat the Yankees, he was the 2007 ALCS MVP for the Red Sox and he's compiled a 7-3 lifetime record with a 3.07 ERA, 0.94 WHIP and 99 strikeouts in 93 2/3 playoff innings.
But Beckett struggled for long periods of the 2009 season. He went 2-2 with a 7.22 ERA in April. In four starts from Aug. 18 to Sept. 2, Beckett allowed 25 runs and 12 home runs in 24 1/3 innings as his ERA ballooned from 3.10 to 3.87.
Which Red Sox hurler held down the proverbial fort while Beckett strayed from his No. 1 status? It was lefty Jon Lester, of course, who went 15-8, finished third in the AL in strikeouts with 225 and became the de facto ace for much of the season. He's overcome cancer, he pitched a no-hitter in May 2008 and he's 42-16 so far in his young career.
But unlike Beckett, Lester, 26, is relatively quiet and less flashy on the mound. His fastball can hit the mid-90s and his breaking stuff is awfully effective, but he's more solid and efficient in his style than spectacular.
Perhaps more telling, though, on whom did manager Terry Francona call for Game 1 of the ALDS against the Angels last October? Lester, not Beckett. Sure, Lester ended up losing the game, but he pitched six innings of four-hit, three-run ball and would have had a shot at a W if it hadn't been for a shutout from L.A.'s ace.
Who was the Angels' No. 1 at the time? Why, a 6-foot-6 right-hander by the name of John Lackey. Lackey, of course, became a free agent after the season and signed with the Red Sox in December for five years and $82.5 million. That kind of money on its own would qualify Lackey for "ace" billing on most staffs around the majors, but in Boston, it only adds him to the mix.
But the 31-year-old has the credentials to back up his big-money contract. Lackey won Game 7 of the World Series for the Angels as a rookie back in 2002 and has proven to be a true workhorse, averaging 30.7 starts and 199 innings pitched a season from 2003-09. He has yet to show his spectacular side — he has won more than 14 games in a season just once, going 19-9 with an AL-best 3.01 ERA in 2007 — but he's been reliable, relatively injury free and steady when it counts, compiling a 3.12 ERA in 12 postseason starts.
So among Beckett, Lester and Lackey, who starts a Game 1 of a playoff series tomorrow? It's anyone's guess. But we're not even done considering the options.
Daisuke Matsuzaka struggled mightily for much of 2009, but this is a pitcher who's just a season removed from an 18-3 record! A longtime ace in Japan, Dice-K came over to join the Red Sox for $100-plus million, has won two World Baseball Classic MVP awards and, when he's on, has one the nastiest pitching arsenals in all of baseball.
Of course, Matsuzaka has struggled with wildness, walks and inconsistency, posting a 1-5 mark and a 7.71 ERA through his first eight starts of 2009. But when he's on, he's on, like at the end of the campaign when he went 3-1 with a 2.22 ERA over his last four appearances. Long story short, Dice-K becoming an ace is probably beyond even Theo Epstein's wildest dreams, but expectations remain high heading into 2010.
The same can be said for Clay Buchholz, who like Matsuzaka, has experienced serious ups and downs over the past few seasons. A high? Pitching a no-hitter in your second major league start. A low? Going a confounding 2-9 with a 6.75 ERA the next season and not even making the major league roster out of spring training in 2009.
But Buchholz, 25, showed that he's worth the praise constantly heaped on him by Red Sox management, winning six straight decisions in August and September last season and making a serious case for a spot in the 2010 rotation. Much like Beckett, Buchholz too has a dazzling combination of heat and junk that can mystify even the savviest of hitters.
Just to make this argument that much more confusing, who remembers who the Red Sox' best pitcher was during the first half of 2009? That would be a 43-year-old knuckleballer by the name of Tim Wakefield. Wake was 11-3 and that knuckler was dancing like mad as he earned the first All-Star invite of his long career. But shortly thereafter, he went on the DL with serious back issues, missed nearly seven weeks of action and made just four more starts the rest of the way.
Still, despite his age and lack of velocity, you'd have a hard time arguing that Wakefield wasn't the Red Sox' No. 1 pitcher for the first few months of the season.
The point is this: An ace is just a title, a largely meaningless designation. Who's the Red Sox' No. 1? Well, it might matter on the opening day of the season or in the opening game of a playoff series, but those are the only times. Each starter in the rotation — as long as he's healthy — is going to get the ball every five games or so. And the team's success is going to depend almost equally on each starter thrown into the equation.
Sure, Beckett has been the guy for the last few seasons, Lester came on last season to challenge him for the made-up crown and the addition of Lackey makes it an ace triangle of sorts here in Boston. (And if Dice-K, Buchholz or Wakefield gets hot for an extended period of time, that triangle could turn into a rectangle, pentagon or — dare I say — an ace hexagon.)
But the honest truth is that it doesn't matter. Real-life No. 1, de facto ace or mound workhorse, it's not the labels that matter, but the wins. And as long as the Red Sox get plenty of those in 2010, the starters can call themselves whatever they want.
NESN.com will be answering one Red Sox question every day through Feb. 23.
Monday, Feb. 8: How will Victor Martinez handle the pitching staff?
Wednesday, Feb. 10: How do the Red Sox cut down on stolen bases allowed?