BOSTON -- Jason Castro was here for the worst of times, and he was gone before the best.

Castro was the Astros’ lone All-Star on their 111-loss 2013 team, their first pick in the Draft five years prior and a player they planned to build around more than a decade ago, without knowing how far off they were from reaching the pinnacle.

Yet here he was in Game 4 of the American League Championship Series, the stakes as high as ever for the 34-year-old -- two outs, two on in a tie game against October linchpin Nathan Eovaldi, in front of a roaring 38,010 and in a batter’s box that’s been graced by more than a century’s worth of the game’s greatest players.

The script had been authored. It just needed a dramatic delivery.

Castro had a 1-2 count against Eovaldi, then had the discipline to lay off a high-and-away curveball that just barely cleared the outer black for ball two. He exhaled as Eovaldi walked off the mound assuming a called strike three -- as did the rest of Fenway Park -- before zeroing back in, hunting anything middle and low.

And that’s precisely where Eovaldi’s next pitch was delivered. Castro yanked an off-plate splitter with authority to right field, sending Carlos Correa surging from second base to score the Astros' first run in a seven-spot ninth inning that evened this series at 2-2 and ensured it will return to Minute Maid Park on Friday.

“I think that's part of a kind of ebb-and-flow series,” Castro said. “Obviously, the last two games before those didn't, but to finish this one tonight the way that we did was special.”

How did Castro get the better of Boston’s best? Eovaldi’s 2018 heroics in the World Series are well-chronicled, but this was the first time he’d been deployed in a much-anticipated relief role this postseason. What was the approach in that tense tussle?

“With his stuff and his velocity and with the way I hit, I'm trying to get something that’s not at the top of the zone,” Castro said. “Where that curveball started … I’m trying to be smart about the pitches I go looking after. Where that pitch started, I didn't think that was a pitch I could pull the trigger on. It was a ball, and I was able to move on it the next pitch. That split was up enough that I could kind of stay through it. You have to respect his fastball with how hard he throws.”

Before considering that Castro is on Houston’s ALCS roster as a backup catcher, consider the challenge he faced when first entering the game in the seventh as a pinch hitter in low-50s temperatures with little time to prepare.

“What impressed me the most was that he was sitting on the bench for seven innings on a cold night,” Correa said. “And you don’t have a batting cage nearby here to warm up or anything, because the ballpark is so old. I don’t know how he did it, but I admire that. I can tell you, I wouldn’t be able to do that. Sitting down for that long, and then facing guys that are throwing 100 in crunch time? That’s special.”

Castro entered the game for Martín Maldonado, in part to help jumpstart an offense that had been the Majors’ best but has struggled to manufacture critical hits -- at least until he broke through in the ninth. And given his contribution, it could foreshadow how Houston approaches its catching situation the rest of the series.

Maldonado is highly valued for his game-calling ability and acumen with the Astros’ pitching staff, but he’s now 1-for-23 this postseason and hitless in the ALCS.

Castro hit lefties for a .561 OPS during the regular season -- well below the .917 mark he had against righties -- and southpaw Chris Sale will start for Boston in Game 5. Despite that disparity -- and given the way that Maldonado has slumped -- a consideration for Castro could be high on manager Dusty Baker’s mind.

Castro left immediately after Houston reached the postseason in 2015, the first of five playoff appearances in the six years after, including a championship parade in ‘17. So, regardless of how this series progresses, the Astro who was here when the times were the darkest shined awfully bright on Tuesday.

“I know he left and came back, and it seems to me like he’s always been an Astro,” said Jose Altuve, the only other Astro on this year's team who went through those three straight 100-loss seasons from 2011-13. “He likes to be here, he loves the team. I’m happy to play with him and I’m happy he’s doing really good like he’s doing.”