BOSTON — When a major-league manager can look down the dugout and realize he has the confidence to insert a bench player into an important situation, that is critical to a club’s success.

Last night, Red Sox manager Terry Francona summoned J.D. Drew and Alex Cora late in the game with Boston trailing the Baltimore Orioles at Fenway Park. Not a bad combination, given the circumstances, but Boston lost, 6-3.

But that won’t be the case every game.

Drew was originally given the night off and replaced with Wily Mo Pena. Cora realistically can fill any role right now because he’s been consistently effective at the plate and in the field. Both Drew and Cora came off the bench in the seventh inning with the Sox trailing by two runs with one out and the bases loaded.

Pena had a horrible night in the field and at the plate, receiving mock cheers throughout the game. When Drew was announced as a pinch-hitter, the 37,039 fans loudly applauded the move. It almost worked as Drew smoked a high liner to the left side that any other normal shortstop wouldn’t be able to make a play on.

But Miguel Tejada is not your average shortstop.

He leaped and snared the hot-shot that would have surely cut the Sox’ deficit. Cora, pinch-hitting for rookie Dustin Pedroia (0-for-3), followed and had his shot to do some damage, but flied 9out to center field to end the inning and the threat.

“J.D. against (Baltimore reliever Chad) Bradford, he took one of the prettiest swings you’ll ever see,” said Francona. “If that ball goes past Tejada, it probably goes all the way to the wall. On a night we needed one hit, we couldn’t get it.”

Even though Drew and Cora were available to come off the bench late in the game, if one or both had started, Francona wouldn’t have had much of a choice as far as bench players. Pena has certainly proven he’s not a good decision to come into the game cold, and the manager’s only other choice is Eric Hinske at this point.

Francona spoke vividly about Pena prior to last night’s game against Orioles.

“Sometimes Wily is all or nothing,” said the skipper. “Sometimes he’s also very good.”

The problem with the backup outfielder and part-time slugger, there’s such a big gap between all and nothing.

Francona continuously talks about giving Pena more at-bats when possible to keep him sharp. Sure, the big man can hit the ball a long way when he’s able to put bat to ball with laser-like precision. But when he leaves the wood in the dugout and straps on his leather glove, it can be difficult to watch.

“I think when you look up at the end of the year he’s going to have a significant amount of at-bats,” said Francona. “It may not be consistent, like every two or three days, but maybe a week in a row when somebody’s nicked up a little bit. That’s the way it’s going to go and he’ll get his at-bats.”

Even the starting rotation is relying on a make-shift starter.

The Red Sox sent Julian Tavarez to the mound last night for his sixth start of the season until lefty Jon Lester is able to return to the rotation. Because pitchers one through four — Curt Schilling, Josh Beckett, Daisuke Matsuzaka and Tim Wakefield — have been outstanding and healthy so far this season, Tavarez has basically worked as a buffer in the fifth spot and hasn’t done too bad of a job given the circumstances

Last night he struggled a bit and worked just five innings, allowing five runs (four earned) on 10 hits with no walks and two strikeouts. A bullpen man by trade, Tavarez is now 1-4 for the Sox this year.

The Orioles got to him early with a pair of runs on four hits in the top of the first inning as Ramon Hernandez and Aubrey Huff each provided a RBI.

The Red Sox responded with two runs in the second inning to tie the game at 2-2 as Julio Lugo provided an RBI double and Manny Ramirez drew a bases-loaded walk to give Tavarez new life.

Baltimore, however, scored three runs (two earned) in the top of the fifth inning that basically ended Tavarez’s night after 90 pitches (62 strikes).

“Early on he gave up a bunch of hits,” said Francona. “But then he started to pound the zone.”

Boston was able to load the bases with one out in the seventh, but could muster only one run, via walk to Jason Varitek, to cut the deficit to two. Again, the Orioles pushed across a run in the top of the eighth and kept the Sox at bay as Boston left a total of 13 runners stranded.

jmcdonal@projo.com