When spring training began, the Red Sox had three aces: Chris Sale, David Price and Rick Porcello.

When the All-Star break hit, they were down to one, Sale. Now, with three weeks to go, Sale still is an ace but one who’s been fading (4.57 ERA since Aug. 1).

The good news is there’s one more starter on the Red Sox staff who can lay claim to the ace label.

The difference between Doug Fister and Sale is the former doesn’t need any qualifiers. Wednesday night’s 6-1 win against the Toronto Blue Jays – Fister’s fourth consecutive start of seven-plus innings allowing two or fewer runs – should be enough to secure his status as the closest thing to a sure thing the Red Sox can put on the mound at this point in the season.

Fister’s arm is relatively fresh, and the 33-year-old has a 4-2 record and 2.60 ERA in nine postseason appearances, eight of them starts.

It’s not just his past four starts, in which he has allowed only five earned runs in 29 innings (a 1.55 ERA). Fister started a little slow, but his overall ERA after 10 starts this season is 3.61. He’s not going to receive any Cy Young votes like Sale, but that’s irrelevant when it comes to Boston’s 2017 team goals.

What he has done is inject himself into the conversation as one of the pillars the Red Sox will lean on when their likely playoff run begins.

“It’s a process, and (I’m) trying to keep continually moving in the right direction,” Fister said. “As the first inning showed, I’ve still got a lot of work to do, but (I’m) still heading in the right direction.”

If by “I’ve still got a lot of work to do” Fister means he needs to stop giving up runs in the first inning like he did Thursday – and in each of his other three first innings in the past four starts, meaning he has given up zero runs in 26 of his innings after the first – he’s being his usual modest self.

Breaking that habit seems like an awfully short to-do list.

“You know, he gets in the rhythm of the game, it takes him an inning, it takes him an inning to find his release point,” Manager John Farrell said. “It’s been uncanny how similar the beginning of games are and how he finishes out. I think, to me, it’s more finding that release point, and then he stays out of the middle of the plate, and then he gets a feel for that curveball, which is, as we’ve come to find out, that’s a key pitch for him.”

Fister’s doing it all right, and at this time in the season when the Red Sox have sputtered against the Yankees and their hold on the AL East has been in jeopardy of evaporating, it’s been Fister, not Sale, who continually has come to their rescue.

“Credit to Doug Fister, plain and simple,” Farrell said. “I think he’s gained a lot of confidence each time he’s taken the mound in the rotation. We’ve talked about the adjustments he had to make, and (he) did those, and he’s gone out and pitched as a veteran does. (He) knows himself, knows how to navigate traffic when it’s on the base paths. You love the body language, the mound presence and the conviction to the pitches. So he has earned that trust by the way he’s gone out and pitched.”

In a way unlike anyone else right now, in Fister, the Red Sox trust.

Dustin Pedroia dove to his right side, spun around and tried to push himself up with his left knee, but fell right back to the ground while making a play during Tuesday night’s 3-2, 19th-inning win over Toronto.

He was removed after playing 10 innings, but even though his surgically repaired knee has caused him two trips to the disabled list this season, he said he is fine.

“He came out of it, actually, after 10 innings he was still in pretty good shape in terms of how his knee was holding up for the duration,” Farrell said.

Pedroia said his knee is “feeling all right, man. Still building up. So far, so good.”

Andrew Benintendi drew his 64th walk of the season Wednesday night – the most by a Red Sox rookie since 1966, when George Scott (65) and Joe Foy (91) each had impressive debut seasons.

One theory about why Benintendi is walking so much? Opposing pitchers don’t want to face him.

“I think it’s as much a reflection of the way teams are game planning against us, because of the August he’s had,” Farrell said. “Let’s face it, we get who’s hot, who’s not and who are you going to pick to attack in tight situations. That might be more revealing that ‘don’t mess with him, go to the next guy.'”