LAS VEGAS — It’s becoming clearer that without trading a significant player off the current roster, it could be a pretty quiet week ahead for the Colorado Avalanche. The Avs signed Casey Mittelstadt to a three-year contract to kickstart their offseason. They can sign Mikko Rantanen to a long-term extension for the 2025-26 season and beyond once the calendar flips to July. But the math is the math, and the Avs don’t have room below the salary cap ceiling to make a big addition to the 2024-25 roster without removing someone who was important in 2023-24.