Last winter, the baseball world was abuzz with talk of an emerging young pitcher. He was a hard-throwing lefty who could lead a team to many wins, the kind of pitcher any team would want.

We're talking, of course, about Johan Santana.

The Minnesota Twins were looking to move their ace, looking for a package of prospects to rejuvenate the franchise while giving up one of the top pitchers in the game.

It was a tantalizing prospect in Boston: Add one of the best left-handers in the game to a rotation that already featured 2007 AL Cy Young Award runner-up Josh Beckett, who went 4-0 in the postseason to help Boston to a World Series championship.

But the Red Sox would have none of it. They were willing to move top young talent to bring the likes of Santana to town, but there was one young man they would not part with to get him.

Now we all know the reason. Monday night, Jon Lester was on the mound for the second time in the AL division series with the Los Angeles Angels – because Beckett, the staff ace, clearly was not himself Sunday night and could not put away an Angels team desperately looking for some life in the series.

Lester has been the team's best pitcher this season. Only four AL pitchers made more starts, and only three had a lower ERA.

The baseball world took notice when he threw a no-hitter on May 19, and it's been hard not to notice him take the mound every fifth day.

Lester is only 24 years old but has the poise of a veteran.

Pressure? Just two years earlier, Lester had to battle for his life after a cancer diagnosis. You have to believe him when he says he wasn't worried about what was at stake before he took the mound for Game 4.

"No, no," he said after Sunday night's game. "I just have to worry about my pitches. I can't worry about us going back to L.A. or the bullpen situation. I just have to worry about going out and executing my pitches. That's all I can worry about. You can't worry about stuff you can't control."

Lester was the surprise Game 1 starter after Beckett suffered an oblique muscle injury, but surprised no one when he gave up just one unearned run in seven innings.

He threw a bulldog-like 117 pitches, refusing to give the Angels any breathing room after Jason Bay gave him a two-run lead with a sixth inning home run.

So there were no concerns when he took the mound Monday night, looking to add to his 11-1 record at Fenway Park in 2008.

Josh Beckett might have the pedigree of an ace, but this season Lester has earned the respect given an ace. Keeping him was one of the best moves Theo Epstein has made in his tenure with the Red Sox.

Johan Santana? Many Red Sox fans wouldn't trade Lester straight up for him if they could.

Tom Caron is the studio host for Red Sox broadcasts on the New England Sports Network. His column appears in the Press Herald on Tuesdays.

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