SAN DIEGO -- The days were long in Arizona.

As he worked his way back from a strained left hamstring, Fernando Tatis Jr. woke up at dawn every day and reported to the Peoria Sports Complex. He worked out, he took part in games at extended spring training, he got treatment. Then, he retreated to his apartment where he watched the Padres from hundreds of miles away.

"Seeing the games on TV, seeing the boys playing, I just wished I could be in the field," Tatis said Thursday afternoon. "It was a very long month."

At long last, the wait is over.

The Padres activated Tatis on Thursday and inserted him at the top of their lineup for the opener of a four-game weekend series against the Nationals, and he went 1-for-2 with a pair of walks and scored the tying run in a dramatic 5-4 comeback win.

Third baseman Ty France was optioned to Triple-A El Paso to clear space.

Tatis, MLB Pipeline¡¯s No. 2 overall prospect, was a surprise inclusion on the Padres' Opening Day roster, and he rewarded their faith instantly. Through 100 at-bats, Tatis hit .300/.360/.550, while playing an excellent brand of shortstop and showing off his elite speed.

In Tatis' absence, Manny Machado shifted to shortstop without any notable drop-off. But the Padres got very little production at third base, and they struggled to find a catalyst to fill the leadoff spot.

"It went a little bit longer than what I expected, what I thought," Tatis said of his absence. "But the important thing is: Here we are. We're good to go."

Tatis was injured on April 28 in Washington while stretching to receive a throw on a forceout at second base. He did a full split and immediately came up hobbled.

On Thursday, Tatis was asked whether he might curtail his aggressiveness upon his return. His response was an unequivocal no.

"I'm not going to lie, I'm going 100 percent," Tatis said. "They can try to tell me to play slower. Sorry, I can't play the game like that."

The Padres don't want him playing any slower. It's Tatis¡¯ full-throttle energy that they've missed as much as anything else.

"It's a long season, and when you've got guys who can bring energy like that, it always helps to have him back around," said Padres first baseman Eric Hosmer. "He was missed."

"It's youth, it's life, the veteran guys feed off of him," said Padres manager Andy Green. "He was in the middle of everything we did when he was here for the first month."

That said, Green noted that Tatis won't play every day upon his return. The Padres have 13 games in the next 14 days, and Tatis will almost certainly sit for a game or two during that stretch.

He only played two rehab games. Most of Tatis¡¯ game-like reps came in Peoria, where the Padres could control the environment. Initially, Tatis hit without running. Eventually, they let him play defense. Finally, they allowed him to run the bases.

On Monday, Tatis joined Double-A Amarillo, where he went 2-for-5 with three walks and a stolen base over two games. That was enough to convince the Padres.

"Feels great to be back," Tatis said.

And, in the Padres' eyes, not a moment too soon.