PHOENIX -- Before the All-Star Game, Hunter Pence sat in front his locker in Chase Field's home clubhouse and talked some Josh Beckett.

"I think, between him and [Roy] Halladay, there are two of the best mound presences in the game," the Houston outfielder said intently. "They have that charisma about them. They have that greatness about them."

The American League didn't get to bask in that greatness Tuesday night. Lingering stiffness in Beckett's left knee cut short his warm-up session, preventing a scheduled second-inning appearance.

According to the pitcher, not a big deal.

"I don't think so," said Beckett when asked if the injury could lead to a missed start. "I could have pitched. I'm not comfortable going out there and getting hurt in the All-Star Game and costing myself starts in the second half. I think that's how everybody should be. This game does mean a lot with the home-field advantage and everything but at the same time there are some important things that are ahead."

He's right. There are important things ahead. And, for the Red Sox, going without the pitcher who produced the kind of imagery painted by Pence for any period of time could be disastrous.

Beckett has become that good. Losing him in the real-life world of the regular season would be a big deal. A really big deal.

"He's one of the best," said Detroit starter Justin Verlander. "He's been incredible this year. Seeing him pitch in person is better than what his stats show, which is hard to do. He's been really, really good."

Jon Lester is really, really good, and he is missing time due to a strained left lat. And Clay Buchholz, who is battling a bad back, can also be classified as really, really good.

So why would going without Beckett be any different than the others? Every pennant-contending team has a pace-setter, and this time around -- with all due respect to Lester and Buchholz -- Beckett is that guy.

He is 8-3 (although the Red Sox are 12-5 when he pitches), carries a 2.27 ERA and league-best .187 batting average against. Beckett has had two stretches this season he classifies as almost as good as anything he has previously put up. ("The difference is that the run in 2009 was like three months long," he said. "That was crazy.")

Beckett set a Red Sox record this season for the most consecutive starts of six or more innings pitched with five or fewer hits allowed (9). His ERA is the sixth-best by a qualifying Sox starter at the All-Star break since 1946.

The stats keep coming.

Starting with his second start of the season, Beckett has had just two starts in which he hasn't gone at least six innings, one of which was due to a rain delay and the other because of the hyper-extended knee suffered on July 8.

"I like seeing him back to the old Josh Beckett where he goes out, dominates a game and tells you how good he is," Lester said. "That's Josh. He's always had that good, confident swagger about himself, and it's good to have that back in our clubhouse."

In spring training, a great majority had a hard time seeing that returning. It wasn't widely known that Beckett's troubles from the year before could be traced back to an injured back of the right shoulder. And the patience of onlookers was tested as the starter went through a spring training in which he went 1-4 with a 5.33 ERA on the way to being named the team's fourth starter to begin the season.

Perception didn't matter for Beckett, however. He was working on refining new pitches, losing bad habits and rediscovering a familiar confidence.

"Everybody in that clubhouse never doubted him and never questioned he was going to get back to who he is," Lester said. "Last year was tough. He had an injury that was tough to come back from and perform. Any time you have an arm injury, it's tough to come back and pitch against guys in September when they've had 500 or 600 at-bats. I don't think anybody in the clubhouse questioned that he was able to come back and pitch. The way he's able to go out and compete and put up numbers is unreal."

"The stuff was there," Beckett explained. "In spring training you have small fields, the wind blows out on half of them. Everything is a little bit different. You know going into spring training there are things you have to do, and this year was the change-up stuff. My fastball was there. My command was better than in spring trainings in the past. It just worked out."

It has worked out. But for the Red Sox to find their way in the second half, it has to continue to work out.

If healthy, there is little reason to believe that the trend set by Beckett this season will be altered. But what Tuesday night did was plant that seed of concern in those already on edge due to the starting rotation's medical issues.

Beckett (who, when asked Monday how his health was, uttered the familiar line, "I haven't been 100 percent since sixth-grade") said while preparing to leave Chase Field folks shouldn't be concerned. 

"I think I would have pitched through it (in a regular season game)," he said. "It wasn't one pitch, it just kind of progressively got a little bit stiffer. I don't know what to say. It sucks to be warming up in an All-Star Game and have that happen. I was in a good situation, I was pitching early in the game, I was going to be able to hang out with the guys for the last few innings. It's tough, but I think I did the right thing here."

It was an analysis that was supported by somebody else involved in the bullpen to-do, American League bullpen catcher Jason Frasier.

"That was the first time I ever caught him so I don't know what's normal and what's not normal. He didn't seem to be hurting a lot, but I don't know his personality," Frasier said. "His stuff looked OK, but I don't know what normal is. The last six pitches or so he just slowed down."

Still, despite all the precautionary measures, the concern will remain. When you mean as much to your team as Beckett does, that comes with the territory.

"When his mind is quiet," said former Red Sox pitching coach, and current Blue Jays manager, John Farrell, "he's one of the best pitchers in the game."