SAN DIEGO -- He's back, and not a moment too soon. A series like this one deserved Fernando Tatis Jr., after all.

The Padres activated their star shortstop from the injured list ahead of Friday's highly anticipated season-series opener against the Dodgers. Tatis then found himself right where he usually is -- at the center of it all.

In San Diego's wild 11-6, 12-inning loss to Los Angeles, Tatis launched his second homer of the season, found himself involved in two of the game’s decisive moments on defense and was frozen on a slider with the bases loaded and two outs in a tie game in the 10th.

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Tatis finished 1-for-6, but the most important takeaway from his extraordinarily eventful night is unquestionably this: That balky left shoulder got a major test on Day 1 -- a ferocious swing on a 410-foot home run in the fifth, then an all-out diving stop across his body in the sixth. So far, so good.

Still, Tatis committed two errors, bringing his startling total on the season to seven. He made a ridiculous diving play in the sixth, but his throw to a late-covering Jake Cronenworth at second base trickled into right field, allowing two runs to score.

“I definitely need to be there earlier,” Cronenworth later said, though Tatis was charged with the error.

Tatis’ 12th-inning misplay was definitively on him. He dropped a toss from Cronenworth while attempting to turn a double play. The floodgates opened, and the Dodgers scored five runs in the decisive frame.

“Great having him back,” manager Jayce Tingler said. “We’ve still got to work in the rhythm and timing on all aspects, but probably more so defensively. I thought his at-bats were good.”

Tatis had spent the minimum 10-day stint on the IL after sustaining a partially dislocated left shoulder on a swing 10 days ago. He’s always had a flair for the dramatic, and Friday night certainly presented the stage -- the first game between the Padres and Dodgers this season after a winter’s worth of back and forth.

A raucous Petco Park, recently upgraded to 33-percent capacity, erupted on Tatis' homer, as he emphatically pounded his chest while rounding first base, then executed his traditional skip around third.

"He's a game-changing player, as I'm sure you all know," Padres center fielder Trent Grisham said of Tatis before the game. "We're excited to have him back. He's very dynamic, and he's very excited to get back. We're pumped to have him in the lineup."

The Padres optioned utility man Tucupita Marcano to clear space for Tatis on the roster. At the time, considering the gut-wrenching nature of the injury, it seemed unlikely that Tatis would be back in the lineup in such short order.

Prior to the injury, Tatis had played in only five games this season, struggling both offensively and defensively. It's unclear whether he was playing through injury at the time. It's also unclear how Tatis' shoulder woes might currently constrain him, if at all. Tatis, who signed a record-setting 14-year contract during the offseason, has not been made available by the club since before the start of the season.

Tatis has dealt with a balky shoulder in the past, and there remains a risk of a further dislocation. If that were to happen again, the possibility for surgery would be back on the table, Padres general manager A.J. Preller said last week.

The Padres and Tatis are pressing on, optimistic it won't recur, so long as Tatis goes through daily treatment and maintenance on the shoulder. The Padres aren't asking Tatis to change his no-holds-barred playing style. But they might ask him to alter some mechanical aspects of his game -- focusing on a two-hand follow-through on his swing and picking and choosing better times for his headfirst slides.

"How can we best minimize risk?" Tingler said. "Look, things are going to happen in the game. We're just trying to do the best we can at talking about -- what are some of the danger points or the high-risk levels? The last thing we want is, here in a couple days, a couple weeks, a couple months, something happening again."