After the game, Seahawks head coach Pete Carroll told reporters Baldwin suffered a sprained MCL.
Baldwin had zero catches on one target before leaving the contest.
Baldwin had a breakout 2015 season that included four consecutive games with at least two touchdown catches from Week 12 through 15. He followed that up by setting career highs in receptions (94) and receiving yards (1,128) in 2016.
He had a slightly down year in 2017, with 75 receptions and 991 yards.
The Seahawks need Baldwin to play an even bigger role this season after an offseason of change. Richard Sherman, Jeremy Lane, Kam Chancellor and Sheldon Richardson are no longer with the team.
Their 9-7 record last season was the franchise's worst since 2011, which was also the last time they missed the postseason.
Brandon Marshall was signed in the offseason to add depth to Seattle's receiving corps, though he's also 34 and coming off an ankle injury last season that required surgery.
Tyler Lockett will take over as Wilson's No. 1 target. Jaron Brown and David Moore should also see an increase in playing time until Baldwin is able to return.