PHILADELPHIA -- Tanner Houck finally looks as if he’s about to drop that swingman label from his job description.

Boston’s talented 26-year-old righty has been used exclusively as a starter this season and it might stay that way.

Houck was mostly effective in Sunday afternoon’s 6-1 loss to the Phillies at Citizens Bank Park, which snapped the Red Sox’s eight-game win streak. He yielded three runs on five hits and one walk over 5 2/3 innings, struck out four and was efficient, throwing 74 pitches (50 for strikes).

“Just going right after hitters,” Houck said. “Getting strike one, strike two, putting them in an uncomfortable spot. I felt like I went out there and threw a lot of strikes, got ahead of hitters early, and kind of fixed the stuff that I felt like I struggled with last outing.”

The competition for spots in Boston’s rotation is about to increase. Veteran James Paxton finished his Minor League rehab assignment on Friday night and manager Alex Cora has stated that the veteran lefty is likely to make his first start of the season next weekend at home against the Cardinals.

That will not impact Houck, whom Cora said is in line to make his next start.

“I'm just going out there that day ready to start, whatever they need. I have always wanted to start. I've always seen myself as a starter,” Houck said. “To have that confidence from AC is great. But I’ve got another one to get ready for.”

In seven starts this season, Houck is 3-2 with a 5.26 ERA. However, the ERA was driven up in his previous outing, when he was the recipient of a six-run barrage in a tough top of the fifth inning by the Blue Jays. The impressive thing about that start is that Houck came back out for the sixth and fired a scoreless frame in a game his team won, 7-6.

Houck has gone five-plus innings in six of his seven starts. He has held opponents to a .254 average and a .688 OPS, and he has given up just two home runs in his last six starts.

“He's been good,” Cora said. “I think he's gone five in most of these outings and given us a chance to win. Obviously, in the last one, he gave us six, but he gave us what we needed.

“So we don't see it by results or whatever. We see it by how he's trending and stuff, you know, and today it was very efficient.”

After breezing through the first three innings, Houck got in trouble in the fourth, including a walk to Bryce Harper that loaded the bases with none out. Though walking Harper isn’t always the worst outcome, Houck was annoyed by it.

“The walk to Harper, I thought was a bad walk, not because of men on, but because it was four pitches after I got strike one on him. It’s about refining those small mistakes and just continuing to push myself to get better each time,” Houck said.

Houck at least minimized the damage, holding the Phillies to a two-run rally.

It was 2-1 and he was still out there in the sixth with two outs, but Cora came to get him when Kyle Schwarber came up with Harper on first. Cora opted for the lefty-lefty matchup and it didn’t go well, as Richard Bleier’s pitch caught too much plate and Schwarber drilled it for a two-run homer.

As Houck continues to establish himself, he will be entrusted to stay in for some of those matchups.

“Yeah, I mean as a friend [of Schwarber’s] and as a competitor, I'd love to go out there and face him,” Houck said. “But I trust AC with everything that I have. If he comes out there and takes the ball, I have full faith in whoever's coming in.”

Meanwhile, the Red Sox are gaining increasing faith in Houck, who could be close to coming of age.

“I love the way he’s attacking hitters. He’s really splitting the plate,” first baseman Triston Casas said. “He’s using the sinker on the inside part of the plate to the righties and then drawing them off with the slider, and then mixing in his changeup to the lefties, which is huge.

“I really like the way he’s going about things.”