BOSTON — Junichi Tazawa was unavailable. That explains a lot.

Tazawa’s absence from the Red Sox’s series opener against the Houston Astros at Fenway Park raised eyebrows, as Boston sure could have used the reliable right-handed reliever in its 12-8, extra-inning loss. But while there were two situations — the eighth inning and the 10th inning — where it seemed like a no-brainer to deploy Tazawa, Red Sox manager John Farrell refrained from doing so.

Allow the skipper to explain.

“He threw a bullpen earlier (Friday). After the bullpen, he was deemed OK and yet advised not to use (in Friday’s game) — to not get him warmed up or hot twice in one day,” Farrell said. “He will be available for (Saturday’s game), but that was the plan laid out for him to get on the mound (before Friday’s game) but not be available (for Friday’s game).

“Otherwise, he would have been in in the eighth or the 10th — in either of those situations.”

The whole ordeal was rather strange because 1) Tazawa hasn’t pitched since Sunday and 2) Farrell said point-blank Friday afternoon that Taz would be available for the first of Boston’s three games against Houston. Yet with the Red Sox scratching and clawing against arguably the best team in the American League, the manager steered clear of using Tazawa because of a plan that evidently was in place.

“After four days down in Toronto because of the workload in Tampa, we wanted to get him off the mound before he was ready to get in a game,” Farrell added of the decision to have Tazawa throw a side session before Friday’s game rather than be available for the actual contest. “But throwing twice in one day after what he had come through, we weren’t going to do that.”

Tazawa threw 30 pitches over 1 2/3 innings Sunday against the Tampa Bay Rays. It marked his highest pitch count since Aug. 18 of last season. But who knew it would sideline the 29-year-old for five full days? After all, it was reasonable to wonder whether the Red Sox held him out of their four-game Toronto series simply because he’s been horrendous against the Blue Jays in his otherwise impressive career.

Nevertheless, Tazawa wasn’t there to save the Red Sox’s bullpen Friday night. And it hurt.

Craig Breslow surrendered a monster, go-ahead home run to Carlos Correa in the eighth inning moments after Boston rallied to tie the game 7-7 in the bottom of the seventh inning.

Then, a short while after the Red Sox tied the game 8-8 in the bottom of the eighth inning, Noe Ramirez made his major league debut in the 10th and allowed four runs (two earned) en route to suffering the loss.

There’s obviously no telling whether the game would have played out differently if Tazawa was available. But sending Breslow back out for the eighth inning was less than ideal. And having Ramirez pitch in his first big league game in a pressure-packed 10th inning was even less palatable.

The Red Sox returned home with some momentum following a 5-2 road trip. That momentum came to a screeching halt as many wondered, at least until after the game, “Where’s Taz?”

Thumbnail photo via Brad Rempel/USA TODAY Sports Images