There's a rumour (from a Boston journalist) that The Blues have made a trade with Boston for Phil Kessel. If Pietrangelo or Colaiacovo are involved, Sydor may be insurance for added depth. Boston couldn't take Jackman, as they need to dump salary.
More likely, however, it's Blues' management getting more nervous about Brewer, and hedging against his being out for the whole year.
I doubt that Sydor has much left. It didn't look to me like he was very effective at Pittsburgh or Dallas last season. I hope they don't choose to play Sydor over Bell.
Bayda is okay, and having him at Peoria can't hurt. I don't see him winning a job on The Blues' NHL roster.
Could they both be invited just to provide a little more competition at camp? (round out the teams?)