WEST PALM BEACH, Fla. -- St. Louis Cardinals outfielder Jordan Walker left the team's split-squad game against the Washington Nationals with left knee pain Tuesday.

Walker departed from the game in the third inning. The team said he will undergo further evaluation.

The 22-year-old Walker, a former first-round pick, has long been considered one of the Cardinals' most talented prospects. But after hitting .276 with 16 homers and 51 RBIs in 117 games as a rookie, Walker substantially regressed last year, hitting just .202 with five homers and 20 RBIs in 51 games with the big-league club.

He wound up playing 85 games for Triple-A Memphis, hitting .263 with nine homers and 37 RBIs.

The Cardinals, who have missed the playoffs the past two season, are counting on players such as Walker to have bounce-back years after doing little to augment the roster in the offseason.

Walker's competing for a job alongside Lars Nootbaar and Michael Siani in an outfield that also includes Michael Helman, who was recently acquired from the Twins.