McClendon began his career at NC State before transferring to Baylor as a graduate student last season. He completed 60.4 percent of his passes for three touchdowns and three interceptions in nine games last year.
McClendon threw for one touchdown and four interceptions in three seasons with the Wolfpack.
Baltimore also signed former Texas guard Patrick Vahe as an undrafted free agent. The team announced both signings Monday.
The Ravens have incumbent starter Lamar Jackson and veteran backup Robert Griffin III as active quarterbacks. Jackson was 6-1 as a starter last season and led the Ravens to their first AFC North Division title since 2012.
Baltimore drafted Penn State quarterback Trace McSorley in the sixth round of last month's NFL Draft.