What can a walk say about a lineup as it readies for the postseason? Everything.

The Red Sox punched their ticket to the postseason with a 5-4 win over the Indians and ace Cliff Lee last night. Though Cleveland’s likely Cy Young winner tossed zeroes on the scoreboard in five of his seven innings, the two innings in which he was touched for runs spoke volumes about Boston’s key hitter in October.

It was not David Ortiz. It was not Dustin Pedroia. It was not Jason Bay. Instead, it was Kevin Youkilis who was treated as the pivotal force in the Red Sox lineup, and rightly so.

“I’m not surprised, whether (Youkilis hits against) Cliff Lee or a fifth starter. He’s very intense, he never gives away at-bats,” said third baseman Mike Lowell. “I know they chant for MVP for Pedroia a lot, but Youk deserves some of those chants as well.

“Not to take anything away from Petey, but Youk has actually been a rock in the middle of the lineup, a big-time run producer and a guy that we’re going to lean on in the postseason.”

Last night offered a worthy prelude. In the bottom of the fourth, Kevin Youkilis followed a David Ortiz double by slamming a two-run homer for a short-lived 2-0 lead.

Tim Wakefield and a faltering Sox defense gave Cleveland four runs in the top of the fifth. But the Sox rallied to tie the score 4-4 in the bottom of the inning on Pedroia’s two-run double.

Lee (22-3, 2.54 ERA) was undeterred. He struck out Ortiz on four pitches. But after dispatching a perennial MVP candidate, the Indians southpaw wanted nothing to do with Youkilis, whom he intentionally walked in front of Bay.

Bay is hitting .303 with a .910 OPS as a member of the Red Sox and who has 31 homers and 101 RBIs in his two stops this year. And yet Lee would rather face him with runners on first and second than attack Youkilis.

The plan backfired when Bay laced a single to center that chased home Pedroia with what proved to be the winning run. Still, it was hard to fault the logic of the Indians.

In four plate appearances last night against the best pitcher in baseball (2008 edition), Youkilis hit a two-run homer (his 27th of the year) and walked three times. That performance continued a trend that underscores the corner infielder’s importance this October.

Youkilis has been nothing short of a force against the best pitchers in the game. Against pitchers with an ERA of 3.50 or less, he entered last night with a .331 average and .974 OPS. Obviously, those marks improved last night.

“He wants to get up against those (elite) guys,” marveled Sox Assistant G.M. Jed Hoyer. “He battles every at-bat like it’s his last. Guys like he and Pedroia, every at-bat, they grind. It’s fantastic.”

Manny Ramirez, whom Youkilis has replaced in Boston’s cleanup spot, entered yesterday hitting .244 with an .838 against pitchers with sub-3.50 ERAs. Albert Pujols had marks of .237 and .814. Alex Rodriguez checked in with a .223 average and .744 OPS.

Such numbers offer a reminder that Youkilis deserves serious consideration as the American League MVP, particularly given his consistent excellence in 2008.

Dustin Pedroia has endured ups and downs, and struggled mightily in May (.260, .295 OBP, .669 slugging). Youkilis, on the other hand, has hit at least .281 in every month of the season, and his OPS has never fallen below .857—at least 30 percent better than league average—in a single turn of the calendar. In short, he has performed at a level somewhere between that of an All-Star and MVP in every month of this year.

“Petey’s obviously had an MVP kind of year, but so has Youk,” said first baseman Sean Casey. “He’s come up with such big hits for us all year long.”

Youkilis has driven in at least a pair of runs in 30 games this year, third most in the American League behind only Rangers slugger Josh Hamilton (37) and Twins masher Justin Morneau (33).

The first baseman leads the Sox in on-base percentage (.390, 6th in A.L.), slugging (.565, 3rd), extra-base hits (74, 4th) and RBIs (111, 4th). By any measure, he ranks among the best offensive players in the A.L. this year.

For the near term, the significance of that development will be felt starting next week. Since Manny Ramirez left Boston, there has been a school of thought that the Sox do not have the needed lineup complement to David Ortiz to allow them to beat elite pitchers.

Everything that Youkilis has done this year undermines that claim. So, too, does the first baseman’s track record in October.

In 15 career postseason games, Youkilis has a .373 average (10th all time among players with at least 40 postseason plate appearances), .459 OBP, .725 slugging mark (7th) and 1.184 OPS (8th).

He was nothing short of a terror last October, especially against the Indians in the ALCS. In that round, he hit .500 with three homers, a .576 OBP and .929 slugging mark, all team-leading totals.

That snapshot strongly suggests that Youkilis can offer lineup protection for Ortiz against the typical onslaught of elite power arms that are found in the playoffs. He may well be the offensive key to the Red Sox’ attempt to defend their title.

For a player who game was once characterized chiefly by an ability to draw a walk and a lack of power, the development is little short of extraordinary.

“I saw him when he came to his first minor-league camp. From there to here, it’s really something,” said Sox manager Terry Francona. “He’s really matured into one of the elite players in the game.”

If that sort of praise echoes is repeated next month, a perceived shortcoming in the Red Sox title defense could turn into a strength. 

Alex Speier is a Senior Writer for WEEI.com.