Jennings is starting in left field and batting second against Toronto. Navarro is catching and batting eighth, one spot behind former Colorado Rockies All-Star Brad Hawpe, who was the designated hitter in his Tampa Bay debut.
The Rays also purchased the contract of outfielder Rocco Baldelli from Durham, recalled catcher Jose Lobaton before placing him on the 15-day disabled list with a right foot injury, and sent right-handed reliever Dale Thayer outright to the Triple-A affiliate.
Hawpe signed a minor league contract last week and played two games at Charlotte. The Rays purchased his contract on Tuesday.