In difficult times it’s comforting to know others who are going through the same struggles. So Cardinals fans who can’t stand left tackle Levi Brown take heart. Fans of most other NFL teams want their left tackles replaced too. The intent here is not to defend Brown who should not have been drafted fifthCQ overall in 2007.CQ Nor is to rip him because what’s the point of adding one more voice to the cacophony of criticism? The Cardinals could make a change at that position sometime during this season. If not it certainly will come in the off-season. The point is this: It’s hard to play left tackle in the NFL. It might be harder than it’s ever been. What makes good left tackles so hard to find? And why are so many of them struggling? I asked a general manager (the Cardinals’ Steve Keim) a scout and an assistant coach for other teams. The scout and coach didn’t want to be identified. Here are some reasons they gave: — Shallow prospect pool. Players at other positions don’t always have ideal attributes: size speed etc. but they compensate in other ways. For example a smaller receiver can play in the slot. A shorter linebacker might have the speed to be a good pass rusher. An offensive lineman lacking great quickness might be able to play guard. But a left tackle Keim said has to be “6-4 to 6-6. He has to have a certain length of arm. He’s got to have enough range and mobility. Then you also get the guys who are long and athletic but they are not physically tough they are more finesse guys ... and then they (defenders) are bulling the crap out of them and knocking them back into the quarterback. “And you also have to be smart enough to learn the playbook. You go out there in the country and there are a lot of big men. There aren’t a lot of big men with great feet great athleticism great range and all of the requirements it takes to play that position.” Said the scout: “You have to take one high in the draft. You just can’t find one in the fourth or fifth rounds. Every school has big guys but the ones who are real athletes they are few and far between.” That makes them hard to get for teams without high draft picks.