If a kid isn't lighting the AHL on fire they're a replacement level NHLer at best.
Nothing to lose sleep over.
Yup... you get occasional guys who don't fit the mold, but generally, if a player can't cut it in the AHL.... there is no way they can make it in the NHL (excluding face punchers like LOB and Rempe). Hell, look at LOC... undrafted, college free agent with little fanfare. He went to the Eagles and earned a big role with the farm club. He got a cup of coffee for it. His second year he proved it wasn't a fluke and earned a NHL job. Now he's a good bottom 6 player. Probably still close to the replacement level as a whole, but a bargain for his contract.
Off topic from here, but the Avs have done a pretty good job of developing these fringe players. LOC, Graves, and MacDonald have helped the Avs to varies extents...but Greer, Dries, Toninato, Sherwood, etc have all carved out NHL roles for periods right after being in the Avs' system. The Avs just don't draft a lot of those types. The AHL isn't really a league where top 6 and offensive defensemen stay long. It is a fairly normal for a year, maybe into a second or in a bit more rare cases complete a second. If they hit the third or fourth year, it is usually off the rails. The guys that stay 3-4 years are the depth pieces. The third liner, 4th line PK guy, complimentary defensemen, etc. If the former top guys don't adapt their game to being role players at that point, they tend to head to Europe or have to be skilled enough to be a top AHL scorer.