He was on waivers and available to any team willing to claim his contract. That was about the best thing you could say about Doug Fister in late June.

Fister was pitching for Triple A Salt Lake City in the Los Angeles Angels organization at the time and had the right to opt out of his contract if he wasn’t added to the major league roster.

The Angels passed, put Fister on waivers, and the Red Sox claimed him. They were desperate for a starter at the time to face, coincidentally enough, the Angels.

Fister took the loss in that game on June 25 but allowed only three runs. That was enough to keep him around, and the Red Sox won eight of the 15 games he started.

In the context of a long season, Fister ranks as a pleasant surprise, some veteran pitching spackle who helped hold things together.

But what he faces Sunday is something else entirely.

Fister is charged with keeping the season alive, the fill-in starter getting the ball for Game 3 of the American League Division Series against the Houston Astros.

The Sox trail the best-of-five series, 2-0, after losing, 8-2, in both games in Houston. If the Sox lose on Sunday, the next game that matters is March 29 at Tampa Bay.

Fister was slotted into the playoff rotation ahead of Rick Porcello, Eduardo Rodriguez, and even David Price, who the Red Sox elected to put in the bullpen when he returned from injury rather than build up as a starter for what would have been this very game.

Price made $30 million this season and Porcello $20 million. The Sox are leaving their Jaguars in the garage and taking a pickup truck to baseball’s prom.

Fister was useful this season but also had a 4.88 earned run average — 9.18 in his last four starts.

Fister faced the Astros at Fenway on Sept. 29 and allowed three runs on five hits over 5⅓ innings. The Sox lost that game, 3-2. But at least Fister gave them a chance.

“We’re turning to him tomorrow to lead the way,’’ manager John Farrell said on Saturday.

For Farrell, every decision remaining in these playoffs will be a referendum on his job security. The Sox have won back-to-back AL East championships for the first time in their history, but the manager may not survive another playoff meltdown.

But then, would any manager keep these Astros down? Houston had an adjusted OPS of 127 this season, the same as the 1927 Murderer’s Row Yankees.

The Astros led the majors in runs, hits, and doubles, and were second in home runs.

Houston took a 2-0 lead in the first inning of both Game 1 and 2, hitting three home runs all told.

“It’s about setting the tone right from the start and that falls in Doug’s hands tomorrow, to put a zero up in the first inning and allow us to capture on the energy here and then build some of our own energy,’’ Farrell said.

“We know getting on the board first is key to that, but we know that we have got to go out and execute. When we didn’t, they have made us pay. But we have seen Doug Fister be able to take a very good lineup and neutralize it in a few starts already this season.’’

Fister also has a 9.00 ERA in the first inning and has allowed at least one run in the first inning of seven of his last eight starts. The exception was his last start against the Astros, the team he pitched for last season.

“A lot of it just is a matter of going out there and getting in a rhythm, and unfortunately it’s taken me a little bit to get in a rhythm sometimes,’’ he said.

“I guess the last outing trying to emulate that again and continue that stretch, just getting going from the first pitch on.’’

The Sox have not yet had a lead in this series. Their last lead in a playoff game was 2-1 in the top of the third inning against Cleveland in Game 1 of the ALDS last season.

The Indians scored three runs in the bottom of that inning when Porcello allowed home runs by Roberto Perez, Jason Kipnis, and Francisco Lindor. The Sox have not had a postseason lead since.

Fister has been in this situation before. He is 4-2 with a 2.60 ERA in nine playoff games — 4-1 with a 1.78 ERA in eight starts.

“He’s not afraid of the big moments, the postseason, the history that he’s had,’’ said Astros manger A.J. Hinch. “So we know we’ll get his best and we need to beat his best.’’

Fister started Game 2 of the 2012 World Series against the San Francisco Giants. He allowed one run over six innings, but postseason savant Madison Bumgarner went seven shutout innings and the Giants won the game.

So Sunday will not be a game that overwhelms Fister.

“There’s nothing to lose with everything to lose,’’ he said. “You’ve got to go in with that mind-set and you’ve got to give everything, leave it all on the field tomorrow night.

“We have got 27 outs to get and 27 outs to give. So we have got a lot of work to do ahead of time and be ready to go. But tomorrow’s going to be a fun day. We can’t look at it as it’s an elimination day. We look at it as an opportunity to continue. There’s only a handful of teams out there continuing right now and we still have a life.’’

Peter Abraham can be reached at pabraham@globe.com.