BOSTON -- Exactly what roles Dustin Pedroia and David Murphy play for the 2007 season remains to be seen. Offseason personnel moves will determine where Pedroia plays and whether Murphy plays at all.

But in the final weeks of this season, this much is certain: the experience the two are gaining is invaluable to their development.

On Sunday, the pair's talent and enthusiasm were on full display. Murphy, hitting leadoff in the first game of the Red Sox' doubleheader sweep of the Yankees, launched his first major-league homer and fairly sprinted around the basepaths.

"It was kind of like, 'Oh my gosh -- I just hit a home run,' " a beaming Murphy recounted.

Pedroia, who wasn't in the starting lineup in the first game, nevertheless made his own contribution later in the game, ripping a pinch-hit, run-scoring double that fueled the Sox' four-run seventh inning.

It was, Pedroia said, his first pinch-hitting experience at any level of organized ball.

"You know what's nice?" manager Terry Francona said. "When these young kids come up to the big leagues, they're (intent) on showing the big-leaguers respect. But the way someone like Pedroia got this far is by being aggressive and excited. I reminded him that's what got him here -- don't be afraid to show that."

Clubhouse comportment is a key for rookies, who want to avoid exuding a sense of entitlement and overconfidence, lest they alienate veterans with 10 or more years of major-league playing time.

Learning how to act in the big leagues is an important part of the maturation process. There are other lessons, too -- handling travel and a new lifestyle included. Getting those lessons learned now will also ease the transition next spring.

"Right now, you're a little out of your comfort zone," Murphy said. "But getting to know the guys, getting adjusted to the travel, all those 'first' things, will help next spring."

Of course, the biggest adjustment of all is on the field, where the level of play is higher than ever before.

"It's a bigger stage," Murphy said. "But the game is the same. The more I play, the more comfortable I get. Things kind of happen in spurts -- first game, first hit, first home run. But performing at this level is just incredible."

Precisely how the newbies fit in next spring is uncertain.

Pedroia seems certain to be part of the Red Sox's double-play combination, but whether that's at shortstop or second base will depend on what else the Red Sox do this winter. If the team re-signs Alex Gonzalez, eligible for free agency, then Pedroia will go to second. Should the team sign Julio Lugo, who has experience at short and second, Pedroia could play either position.

As for Murphy, his role is less defined. The Sox project him as a right fielder, and with the incumbent at the position, Trot Nixon, not expected to be re-signed, an opening should develop. But the Sox are intent on getting increased playing time for Wily Mo Pena, leaving Murphy without an obvious position.

A platoon of the two would be unwieldy, since the right-handed-hitting Pena would receive far fewer at-bats, defeating the idea.

In all likelihood, Murphy will serve some sort of apprenticeship as a backup outfielder at all three positions. The fact that he hits left-handed will be a bonus.

The tricky part for the Red Sox is evaluating the two fairly in the final weeks. Personnel experts frequently warn of the dangers of judging players in March and September, when performance can be misleading.

The task is made more difficult for Francona, who feels a loyalty to infielders Alex Cora and Mark Loretta and outfielder Gabe Kapler, all of whom stand to lose playing time so that the Sox might get a better read on Pedroia and Murphy.

But on days like Sunday, when both players contributed to wins, it all seems less complicated.

"It's really fun to have the young kids have a little bit of success," said Francona.

smcadam@projo.com / (401) 277-7340