Add to that the general acceptance of veterans as having paid their dues. So mistakes from a veteran are often accepted while the same error by a youngster is proof he isn't worthy of being in the majors.

The past two days we've heaped tons of scorn on Cedeno and Murton when neither was primarily responsible for the loss.

I went back and looked at the discussion of Hill last year and it generally was a 50-50 breakdown of ship him to Siberia or he'll be OK in time. Imagine if we had bailed on him last year?

So, in summary, there is no generally accepted test for measuring youngsters. Sometimes the debate itself is worth the price of admission to the club.

murton is a little different because he's a corner outfielder. so i expect more offense out of him. i would definitely take his stats from last year. but i'm underwhelmed with what i've seen of him this year. he's not taking pitches like he used to, and he's not going opposite field. he doesn't have enough power to be useful if he's not gonna hit around .290, or get on base at a .400 clip. those are high standards, but that's what comes with corner outfielders i think.

Cedeno is worthless and that's all there is to it.  You needn't look any further than his minor league numbers to see that.  

Murton is not worthless and I never said he was.  I said he's a marginal left fielder and marginal means he has some value.  He's not ever going to be a great left fielder.  Yes, his defense is better than some suggest it is.  He has more speed than people give him credit for yet it doesn't really show up very much (not scoring from 3rd on two different plays would be a great example here).  Last year he was ranked, by VORP, as the 17th best left fielder (400 or more plate appearances if I recall correctly) out of 29 or 30 left fielders. Among 2006 left fielders with 350 or more plate appearances, he ranked 20th out of 32 in VORPr.  

He's not a player who is going to improve much.  He's an extreme groundball hitter and these players tend to decline more rapidly than they improve...even at a young age.  As a result, it's unlikely he ever hits for much power (in 2006 he was 19th in slugging).  His on-base skills, as his speed deteriorates, will decline somewhat (despite all the love for his on-base skills, he ranked 10th in obp among left fielders with 350 or more plate appearances).

I could go through almost any other stat and we'd see that Murton, overall, is a below average left fielder.  Maybe that's good enough for you.  But that is the precise definition of marginal.  He has some value, but NONE as a starting outfielder.  

You can compare him to vets all you want, but until you begin to compare him to players with similar skills, it's meaningless.  His top 20 comparables according to BP are Rondell White, Rick Reichardt, Chad Allen, Alex Ochoa, Luis Matos, Aaron Rowand, Gil Flores, Gabe Kapler, Bernie Williams, Mark Whiten, Bob Watson, Dmitri Young, Carlos May, Ken Berry, Mike Darr, Hal Morris, Lee Walls, Glenn Braggs, Tony Horton, and  Glenn Wilson.  

Not exactly a bunch of studs among those players, are there?  He's a marginal left fielder.  IT's really that simple.  You're free to believe otherwise and ignore all the stats that are available to you if you wish, but it doesn't make him better than slightly below average.  

As a cheap outfielder, he's just fine.  When he reaches his 2nd and 3rd year of arbitration, however, see ya Matt!

Marshall comes to mind. To further answer what is acceptable for either rookies or 2nd year players. I thought Marshall had an acceptable year as a rookie. He showed flashes of being a good pitcher. In this case his W-L record and ERA were not that great, but you saw the potential in him. I am holding out hope that yet this year we get to see him pitch with the Cubs.