In some ways, Fletcher has had to overcome longer odds than Rams quarterback Kurt Warner, who rose from the obscurity of the Arena Football League to become NFL MVP.
Not only did Fletcher have his size working against him, he had to overcome the stigma of playing at tiny John Carroll University -- a Division III school in Cleveland -- before he could get a shot to join the Rams as a free agent.
"London Fletcher goes way beyond a story," Rams Coach Dick Vermeil said. "That kid is real. He's real. He is nonfiction. He caught my attention about midway through his rookie training camp two years ago.
"You just kept watching him, and we'd go to personnel meetings and would hear our coaches and scouts say that for a little guy, he really plays pretty good."
Much like the Rams' defense itself, Fletcher is more than a bit underrated. After winning a three-way battle for the starting spot between Charlie Clemons and Lorenzo Styles, Fletcher led the team in tackles during the regular season with 138.
"I play the game the way it should be played," Fletcher said. "I try to go out there with an all-out approach to the game. I try to be as aggressive as possible and try not to worry about making a mistake."
The biggest surprise about Fletcher's rise to mini-prominence in the NFL is that he did not play football at John Carroll -- which is the same school that produced Don Shula -- until his junior season. His collegiate athletic career actually began as a point guard on the St. Francis (Pa.) basketball team, where he had a full scholarship.
"It just got to the point where basketball wasn't fun for me," Fletcher said. "For anybody who has ever seen me play, they know that I like to have fun no matter what I'm playing. In basketball, everything that transpired at that time led me to football."
Division III colleges are not permitted to give athletic scholarships, so Fletcher had to pay his own way to school with the help of a few student loans and grants. He graduated with a degree in sociology before turning his postgraduate attention to the NFL.
At John Carroll, Fletcher was reunited with his former high school basketball and football coaches. It was during his senior season that he began to think seriously about the NFL, even though this league does not usually take 5-9, 240-pound linebackers quite so seriously.
"In the second game of my senior season, I had 29 tackles in a ballgame," Fletcher said. "I had been hearing from coaches who had had experience in the NFL. They felt that I had the talent to make it in the NFL, but you really don't know how much of that is true.
"But after that ballgame, I kind of said to myself: 'Man, you're pretty good.' That gave me some confidence, and I had always felt that if I was given an opportunity and I put my mind to it -- whether it was academically or on the field athletically -- I feel like I can do it."
Fletcher reportedly arrived at Rams training camp last season with less than $20 in his pocket, but he carried a big-enough chip on his shoulder -- from having been passed over in the NFL draft -- that his skills became pretty evident in the first couple of days.
Vermeil took notice.
"I have never evaluated a football player other than how he plays," Vermeil said. "He kept catching my eye. Then we put him on special teams, and he got to where he would dominate on special teams.
"We started him the last game of the  season when Eric Hill was hurt. He [Fletcher] played the position better than it was played all year. Therefore, we didn't bring Eric Hill back, and Eric Hill did a good job. It was no bad reflection on Eric Hill. It was just going to provide a kid who had some real talent a chance to play."