By night's end the loss on the scoreboard was overshadowed by the loss of the Padres phenom.
Fernando Tatis Jr. exited after a sixth inning at bat, in which he hobbled after a swing and grabbed his lower back. Andy Green and a team trainer checked on Tatis, who finished the plate appearance with a strikeout. After spending more time with the trainer, the 20-year-old shortstop exited the dugout.
The team called the injury a lower back spasm.
Andy Green said after the game that Tatis will not start Wednesday's series finale against the Rays, and they will see how he's doing after a day off on Thursday. He added that they don't believe the injury is "overly severe".
Tatis missed more than a month earlier this season with a hamstring injury. Green said they had discussed giving him a rest day prior to Tuesday's injury.
The injury punctuates a third straight loss for the club. San Diego struck out a season-high 18 times in the 7-5 loss.
Luis Urias had a career-high three RBI in the loss, after a two-out double cleared the bases in the first inning and gave the Padres a 4-1 lead.
Tampa answered with six straight runs. Ji-Man Choi put them ahead for good with a two out, two run home run in the seventh inning.
The Padres will try to avoid a fourth consecutive loss Wednesday, when the teams wrap up the series at 12:40. Urias will play shortstop in place of Tatis.