If they did, the team isn't saying anything about it. Witherspoon joined the team late in July, right before the start of training camp. The Rams did say they were prepared for Dunbar's suspension. As ESPN's Rams blogger Nick Wagoner points out, it's quite possible that Witherspoon was a backup plan.
A player and his team get notified of a looming suspension well in advance of the public. Obviously, that leaks out in some cases, but that's not a designed part of the process. Suspensions are not announced until the appeal process has been completed or foregone in the first place.
I said earlier that Dunbar would not appeal, but that's not clear. He might have already appealed and lost his case. The Rams allowed just one question on the matter Wednesday afternoon, according to Jim Thomas.
Media allowed to ask Dunbar only one question; Coach Jeff Fisher not made available to the media.— Jim Thomas (@jthom1) August 14, 2013
The question now is whether or not Witherspoon can be an adequate replacement for Dunbar. According to Pro Football Focus, Dunbar was the team's highest graded linebacker last year, with an overall rating of 2.2. He was especially effective against the run, leading the team with 62 stops (i.e. tackles that result in an offensive failure).
Witherspoon, 33, only played 393 snaps, but he graded out poorly, especially in run defense. His -10.9 grade was the second-lowest of any Titans player against the run.
According to Football Outsiders, Witherspoon's stop rate was just 45 percent, lowest on the team and ranked 110th in the NFL. Dunbar's stop rate was 72 percent, and his 17 defeats on run plays were fourth most in the NFL. It's worth noting that Dunbar had never experienced that kind of success in four seasons with the Saints.
Football Outsiders said this about Witherspoon's time in Tennessee, in the 2013 Almanac:
Will Witherspoon was a sad example of what happens to space players when veteran savvy can no longer compensate for declining physical ability.
Dunbar's out just four games, but the Rams face a tough stretch of the schedule during the season's first month. They play the Cardinals, Falcons, Cowboys and 49ers. Of those four opponents, there's a lot of running.
The most conspicuous opponent of the bunch is San Francisco, which runs and runs well out of the pistol and mixes in plenty of read option with Kaepernick, Frank Gore, LaMichael James, etc. Dunbar played a crucial part in St. Louis' tie and win over the 49ers last year, totaling 15 tackles in both games. He had nine in that Week 13 overtime win.
If the Rams are going to get by without Dunbar for their first four games, there's more of an onus on rookie Alec Ogletree to get up to NFL readiness in a hurry, something he did not show in the preseason opener. Ogletree is the most athletic linebacker of the bunch, and without Dunbar, he'll have to carry a bigger load as both the nickel linebacker and a sideline-to-sideline linebacker capable of chasing down backs.