I don’t know about NFL, but I think I’d buy the number for Samoans getting into prowrestling.
Here’s a wiki addressing this very topic
The article was already cited in post #16, and as I mentioned there, doesn’t contain any authoritative cites for the figures it includes. In particular, the statement “28 of them were from American Samoa” is directly contradicted by its own citation. I wouldn’t trust any of that information.
Lemme throw in a bit of stereotype about Samoans. I lived in Hawaii for several years, and heard things like this a lot, and I am under the impression that this is generally meant as a good-natured jab, and that Samoans take it in in a friendly attitude as well:
The stereotype is that Samoans are all big husky heavy guys – This would make it sound like they are ideal candidates to be football players. Maybe that’s all there is to it.
We had a research lab at the marina, with a big salt-water tank containing some dolphins. Occasionally a dolphin would fall out of the tank onto the surrounding concrete deck. (Thud!) So we’d have to dig a stretcher out of the storage room, wrestle the dolphin onto the stretcher, and lift that up to dump the critter back into the tank.
Dolphins are heavy!
The standard joke always was: Go out into the marina and round up four husky fisherman to help us – or ONE Samoan. 
My father was a professor at U.H. who taught extension for one semester in American Samoa. He has a similar “stereotype” Samoan story to tell: That, like the stereotype Irishman, they love to get drunk in bars, and get into knock-down bloody brawls – and it’s all in jolly good fun, and after it’s all done and the blood is cleaned up, they’re still good buddies just as always. (I suppose we could call it “recreational brawling”.) Just like a good knock-down brawl ought to be!
One of my father’s students (both in Samoa and in Honolulu) was a genuine Samoan High Talking Chief, with an “exotic” Samoan multi-syllable name. IIRC, I met him a few times when I was a teen-ager there. I believe he fit the “big husky guy” stereotype perfectly. I don’t know if he was into brawling, but I suspect that he would have taken it as a good natured standard Samoan jibe.
ETA: That HTC apparently is somebody who’s somebody, or else his name is a common one. Googling (both his first and last name), I find a whole lot of references, including a Facebook page. (Well, I assume it’s the same guy anyway.) And I see a number of football players with the same last name too. I’m thinking he must be in his mid-70s now.
That’s pretty much it, I think. Many Samoans do fit the size stereotype, but I have actually known scrawny-looking Samoans.
Former football encyclopedia editor checking in…
The OP referenced players “born in Samoa” To date, there have been 29 players in the NFL born in American Samoa, 6 from Western Samoa, and 1 from Samoa. There were 5 active during the 2012 season.
The whole premise is a fallacy, the idea that it’s unusual for a region that size to produce that number of players. Gary, IN, Tyler , TX, and Albany, NY are all cities with populations under 100,000 that have produce more NFL players than American Samoa.
There’s some selection bias here, but there’s also the issue that there will be geographic pockets of excellence in any skill. The Dominican city of San Pedro de Marcoris has produced 80 major league players, and 10 percent of all MLB players come from the DR – both disproportionate numbers. It’s because most of the teams have baseball academies there to train young players, and baseball is a huge focus. Same thing is true of American Football in American Samoa… and Tyler, Texas.