I know he's had a few failed opportunities to stick with the parent club either in call ups (11 games, 3 points) or winning a roster spot out of training camp but what's wrong with this guy???

At 24 years now he's reaching his make or break point to be a legit NHL player.  Granted he was only converted from defenseman to forward in 2003 while in the WHL but you have to imagine he gets it by now.  Purely based on numbers he's been Rochester/Portland's most consistent forward the last 4 or 5 years.  Put that with several AHL all-star appearances and he's got a great minor league resume.

Year                GP   G   A    P  PIM  +/-

2005-2006     71  18  24  42  80  -1
2006-2007     64  23  34  57  49  +1   
2007-2008     73  29  38  67  61  +9
2009-2010     80  21  36  57  78  -7
2009-2010     60  22  38  60  51  +14

I read one of his knocks is that his success has come because he plays with good players (Corey Locke, Nathan Gerbe, Tim Kennedy, Tyler Ennis, Clarke MacArthur) but that's what happens on any top line.  With his excellent size (6'4" 225)  and tremendous shot (AHL record 102.8 MPH), I see him as an ideal 3rd/4th line winger with powerplay upside.  Having played defense I'd love to see him inserted at the point on our 2nd PP unit, hoping for Alex Kotalik type production without as much defensive liability.

He's in the final year of his contract and will be a RFA this offseason so a contract decision looms with him from Darcy  Does anyone know what his issues are and why he hasn't been given PT on the sabres?  I'm at a loss.

UPDATE:  Some insight from a 9/2009 post by Dave Olesky paints a better picture:

We'll start with Mancari since he is still a restricted free agent with no intentions of signing with the Sabres.  It appears that Mancari is hoping to sign with a club that is willing to give him a shot at playing in the NHL.  It doesn't look like that chance will come in Buffalo with the depth the Sabres have at forward.

Most of us have not had ample opportunities to see Mancari play live and we relied on statistics and highlights.  We knew that he put up great offensive statistics and had a monster shot.  We didn't know how he actually played the game.

I always wondered why the Sabres never gave him a real shot to play in the NHL.  I stopped wondering after talking to people in the know.  It appears that Mancari is primed to be a career AHL player or a fringe NHL player.  Despite his large 6-3 220 lbs. frame he plays a soft game and is reluctant to battle in the corners.  He is also a very slow skater and has trouble controlling the puck in traffic. 

It looks like we know why the Sabres have been reluctant to give him a shot.  He seems content to play the same style and go somewhere else instead of working hard and trying to earn a spot by playing physical.  The Sabres would love to keep him around in case he ever realizes his potential but they will not give any gaurantees.  Can you blame them?