With Sams knee he was a dead man walking. There is no telling if he can even play at full speed again(which was slow) and if he can play this year he is just another tap on the shoulder, a la Carson Palmer, away from another crippling injury.
Knees can also affect the back and throwing motion and psyche. Sam was broken and Fisher and Snead didn't keep Danny for the same reason and let SJ move on despite being the best back on the roster at the time because of age and injury. Trading/Cutting Sam fits right in with their attitude about having players on the field. I said it at the end of the season. Winning franchises would move on from Sam and losing ones would hang onto him in desperation. It is a hard pill to swallow but they had to do it, or be prisoner to Sams health, hoping and praying that he can hang on for an entire season every year. We did it with Setterstrom and it is a no win situation.
Think of the Cardinals this year. They kicked butt in the regular season and limped into the playoff picture without the guy that got them there. That would be the Rams every year that Sam was the QB. No thanks.
It is like getting out of a bad marriage. She might be hot and all but if it is just not working out you have to bite the bullet and do it.
I like the trade, just wish they hadn't swapped firsts. The cap savings is big for a little while anyway.