Johnson left Syracuse last week, shortly after the school announced that coach Jim Boeheim would be retiring in three years. The Orange were hit with scholarship reductions earlier this month by the NCAA, meaning the program could use only 10 scholarships per year -- instead of the usual 13 -- for a four-year period.
Johnson, a 6-foot-7 forward, averaged 4.2 points and 3.2 rebounds per game this season. He saw more minutes toward the end of the season, including a 19-point, six-rebound performance against Notre Dame in late February.
La Salle has had success with transfers over the past few seasons, with Ramon Galloway (South Carolina) and Tyrone Garland (Virginia Tech) helping lead the Explorers to the Sweet 16 in 2013 and Jordan Price (Auburn) leading the team in scoring this season.
After sitting out the 2015-16 season, Johnson will have two years of eligibility remaining at La Salle, where his father Robert also played.