I think you got some facts confused here. He was never traded to St. Louis. He was drafted by San Jose, traded to Buffalo as part of a package for Campbell. Buffalo traded his RFA rights to Vancouver at the end of his ELC. He signed an 1 year offer sheet with the Blues. Vancouver matched. So he played a year in Vancouver. After that year, he re-signed a 2 year deal with Vancouver who still held his RFA rights. According to General Fanager, who gets its info from CapGeek, his status at the end of the 1 year offer sheet was still RFA. He gained UFA status at 26 because he was still an RFA, but Florida who then owned his rights chose not to qualify him. Here's a
link to an article saying Florida chose not to qualify, long after the offer sheet.
Year - Age ----Contract - Team - Contract status after season
05-06 - 20 yo - ELC1 - Sharks - under contract
06-07 - 21 yo - ELC2 - Sharks - under contract
07-08 - 22 yo - ELC3 - Sharks/Buff - RFA (Buf owns rights)
***Buff trades to Van/Blues Offer sheet/Vancouver matches****
08-09 - 23 yo - OS1 - Vancouver - RFA (Van owns rights)
**Vancouver resigns him **
09-10 - 24 yo - 2ndRFA1 - Vancouver - Under contract
**Traded to Panthers**
10-11 - 25 yo - 2nd RFA2 - Florida - RFA
**Florida does not qualify, gains UFA, Signs with NJ**