James Paxton joined the Red Sox starting rotation on Friday, giving Boston six starters. His solid outing gives Boston hopes of finding five capable starters to help them battle for a playoff spot. Michael Dwyer/Associated Press

What exactly are the 2023 Red Sox? Are they a last-place team? Are they a playoff contender?

As of this moment they are both. Entering Monday, they sit in the basement of the AL East, arguably the strongest division in baseball. And yet they were just a half-game out of an American League playoff spot.

We’re just one-quarter of the way through the season, and we will learn a lot more about this team in the six weeks between now and the Major League Baseball trade deadline. The biggest lesson will come from the starting rotation.

Quietly, that rotation has started to come together in recent weeks. Manager Alex Cora currently is using six pitchers in that rotation, something he and most big-league managers do not like to do. Six starters means one fewer reliever, putting added pressure on the rest of the bullpen.

Cora has made it somewhat clear he will not keep a six-man rotation forever. Yet the current group will remain intact through this coming weekend’s series in San Diego. So far the strategy has paid off.

Over the past six games Red Sox starters have averaged 5 2/3 innings per start with an ERA of 5.07, that’s more than a run lower than their season-long ERA. They’ve struck out 34 while walking 10.

Those numbers are inflated by Nick Pivetta’s brutal four-inning outing in Philadelphia in which he gave up seven runs on eight hits. The remaining five starters have a 3.64 ERA and a 1.08 WHIP over this six-man turn.

All signs point to Pivetta being the odd man out. Yet these things can change quickly, with one bad outing or an injury. Tanner Houck has made more career appearances as a reliever than as a starter and is always a candidate to move to the bullpen, but the Sox had won five of his seven starts before Monday’s game.

And things will get more crowded. Garrett Whitlock will make a rehab start in Worcester on Tuesday night. He’ll probably make one more minor-league rehab start after that. “Then we’ll decide what to do,” said Cora over the weekend.

That could mean moving Opening Day starter Corey Kluber, whose 6.41 ERA is the highest on the staff. He was beaten Sunday night as the Sox were swept by the Cardinals. Boston has lost five of his eight starts.

Brayan Bello, 23, is coming off a dominant performance against Atlanta and could be a cornerstone of the rotation for years to come. He’s not going anywhere. Houck continues to work on a new cutter and has refined his splitter in an effort to be a pitcher who can go deeper into games as a starter.

“Just continuing to work, continuing to push yourself,” Houck said last week. “I know everyone says it, but trusting the process of showing up every day and doing the right things and putting in the small detail work — it really does pay off.”

Houck, Bello, Chris Sale and James Paxton combined for 24 2/3 innings, allowing just eight earned runs, striking out 27 and walking four in their last starts. Those are the kind of numbers nobody expected this season.

If Cora can find the right fifth man for that rotation the Sox could continue to exceed expectations this summer. If not, they may be headed for their third last-place finish in four years.

In the meantime, the Sox continue to show us both versions of themselves. Their recent eight-game winning streak led us to believe the playoffs are a possibility this year. Losing five of six since put them back in the bottom of the division. The sum total is a 9-5 stretch of baseball that has built both optimism and concern.

Tom Caron is a studio host for the Red Sox broadcast on NESN. He is a graduate of Lewiston High School.