Not necessarily. Often teams will label a guy day-to-day but as that situation approaches 7 actual days then realistically he needed to be on IR. Paajarvi got injured Saturday, so assuming they made the IR thing retroactive a week he could be eligible to come off the list and play soon, just likely not this weekend. Once the Blues determined he wasn't healed enough to get in the lineup this weekend they likely made IR official and retroactive. The NHL wants its teams to provide accurate injury reports (same as football, etc.) so if you think an injury might heal in 4-10 days you start out with day-to-day designation and then when it starts looking longer you retroactively put a guy on the IR. That's what I think is going on here. Now, he may be out awhile, who knows, but I think if it were obvious he'd be out multiple weeks they'd have put him on the IR immediately but since it wasn't they didn't ... now just doing it to not run afoul of the league.