B-R and Fangraphs have modified WAR based on a team with a .294 winning percentage as replacement level. Essentially, 47 - 48 wins. This is based on about 1000 wins over 30 teams palying a 162 game season. This is still roughly what a team of Rick Ankiels, Chris Youngs, Chris Snyders, Dice-Ks, etc... could win. Guys who signed over the offseason to minor league contracts with invites or were waived. Minimal cost to acquire. It is explained here
. Also, it is the level at which all but one player who has played 10 years has exceeeded (these guys were able to stick in the majors a long time soe were likely better than replacement).
A lot of the difference in Br-WAr and f-WAR was based on a different assumption of what replacement level was. FG tended to give more credit for longevity because it assumed a lower replacement level. Thus, guys like Brooks and Yaz who played a long time were rewarded more in their career WARs at FG. Was it Woody Allen who said half of life is just showing up? That was why FG had Jack Morris at a higher WAR than BR. It was not due to the use of FIP v. an adjusted runs/ 9.
Cameron writes about why use a replacement player as a baseline here.
Basically, this rewards a player who may be below average but plays full time over the guy who was even worse that he beat out.