McAdam: How much stock can the Red Sox place in September performance by rookies?

Former Red Sox manager Jimy Williams, a superb teacher and good judge of talent, was fond of saying: "The two toughest months to evaluate players are March and September.''

His point was this: too many evaluators fall in love with players who perform well when it doesn't matter -- in March, before the games count for real and the competition isn't up to par; and September, when young players, promoted by teams out of contention, play in games with little meaning and even less pressure.

Beware, Williams warned: Prospects in the final month of the season may not be who they seem to be. Opponents are unfamiliar with them and have yet to make the adjustments that will come in time. A few weeks of pressure-free baseball isn't the best laboratory to determine who can play and who can't.

That's the dilemma the Red Sox currently face.

Their nightly lineup is full of players they hope will be part of the organization's rebuild. There's first baseman Bobby Dalbec, who got everyone's attention when he homered in five straight games recently. There's Christian Arroyo, who's posted an .849 OPS in the last week while trying to claim second base for himself. And there's Tanner Houck, who tossed five shutout innings to win his major league debut Tuesday night.

Together, the trio have made watching otherwise meaningless games interesting, even compelling at times.

But is there a risk in reading too much into what we're seeing? The Red Sox are trying to balance it all out and find the proper context. The aim is to get a sense of how close a particular player is to having an impact and what parts of the game still need additional development or improvement.



Against that backdrop, it's important to be as observant as possible.

"I agree that March and September are a little more difficult (times to evaluate players),'' said Ron Roenicke. "But I still think in September, you can see a lot. You can see how hitters react to Houck's pitches. And I think just watching the opponents -- and we're playing some good teams who are going to be in the playoffs -- you can tell a lot. I still think you get a good read on what guys can do.''

"I do think that the new September rules (in which rosters are no longer expanded to as many as 40 active players) make it more like the rest of the season now,'' said Red Sox chief baseball officer Chaim Bloom. "But even without that, the regular season is always very meaningful, no matter where you are in the standings.

"The biggest issue in my mind is the small sample size. Performance can fluctuate so much in this game over short periods of time So we have to be careful making quick judgments and we have to make sure that no matter what the sample size is, we've judging guys not on surface results, but on the things that are most predictive.''

Projecting who's ready to make the jump can be tricky. Perhaps two of the best homegrown Red Sox players of the last 25 years had abysmal introductions to the big leagues in September.

In 1996, shortstop Nomar Garciaparra hit just .241 in 24 games. There was nothing to suggest that he would go on to win two American League batting titles or finish in the Top 10 in AL MVP voting in each of his first four full seasons.

Similarly, Dustin Pedroia slashed a paltry .191/.258/.303 over 31 games in 2006. Manager Terry Francona found it hard to hide his skepticism when the front office pegged him as the second baseman for the following season. Of course, as he often did in his career, Pedroia proved many doubters wrong when he won Rookie of the Year in 2007 and AL MVP in 2008.

Sometimes, players feel overwhelmed at first and aren't comfortable enough to let their natural abilities take over.

But even in a time when the amount of data available can be exhausting, beyond the numbers, there are strength and weaknesses that can be identified.

"We can get a read on what a guy does,'' said Roenicke. "Is he patient? Does he chase out of the zone? Does he square up the mistakes? Does he drive the ball to the gaps? So there's an awful lot there that we're able to see.''

If trying to glean something meaningful from a position player is a challenge in the short-term, doing so with pitching is even more problematic. There are so many variables -- quality of the opposing lineup, game conditions, defensive play behind the pitcher, etc.

There are no absolutes and the biggest mistake teams can make is to put too much emphasis on small sample sizes -- good or bad.

"Just like we wouldn't be down on Tanner if he had been hit around (Tuesday) night,'' said Bloom, "we're not going to change our opinion of him because he had a good game. But it was still great to see. I loved his aggressiveness, especially against lefties -- that's something he's been working on. How he threw validated a lot of his work in Pawtucket.''