Pereira thought the pass should have been ruled uncatchable. That was my feeling upon seeing the play live. The more I studied replays, the more I understood the call.
The 49ers' Troy Smith threw the ball from his right hash to between the hash and the yard-line numbers. Tight end Delanie Walker was standing along the yard-line number on the same side of the field when he tried to make a play on the ball. Rams safety Oshiomogho Atogwe was not looking back at the ball when he and Walker collided. Had neither player been looking for the ball, the collision could have been considered incidental contact. Walker was clearly looking back at the ball and trying to catch it.
Officials must classify the ball as "clearly uncatchable" when deciding against calling interference in such a situation. Walker would have had to cover about five yards quickly for any shot at catching the pass. Could he have done so if Atogwe hadn't knocked him down? Probably not, in my view. Smith appeared to be avoiding a sack as much as he was trying to target Walker.
The difference between "probably" and "clearly" might have cost the Rams a shot at their first road victory of the season.
These situations can often help refresh our understanding of the rules.
On a side note, referee Ed Hochuli and crew entered the Rams-49ers game tied for the NFL lead this season in most interference penalties with 12, according to ESPN Stats & Information. Hochuli's crew called 17 last season when the league average was about 12 per crew. Numbers for Hochuli's crew were more in line with league averages in other recent seasons.