By Michael Hurley, CBS Boston

BOSTON (CBS) — Going back to the spring, expectations for the 2021 Boston Red Sox were almost nonexistent. Most folks were hoping to simply see a watchable, inoffensive product on TV more often than not.

READ MORE: Coronavirus In Massachusetts: Today's Developments

Obviously, with a 22-13 start to the season, things have changed considerably. They’ve reshaped the outlook for their whole season, turning a postseason trip into a real possibility for the first time since 2018.

That’s all well and good, but this week, after a kick-in-the-stomach type of loss on Tuesday night to the A’s, we get to see how good the Red Sox really are.

This week’s series against the A’s marks the Red Sox’ third series against a team that’s currently in first place. Boston surprisingly swept the brief two-game set with the Mets in Queens, beating Jacob deGrom in the process, and they split a four-game set at Fenway against the White Sox.

Now if they want to win the series against the A’s, who sit in first place in the AL West with a 22-15 record, they’re going to need to shake off the sting from Tuesday and win the two remaining games.

In the larger scheme of the 162-game season, there’s obviously nothing really at stake. But winning a series at home against a top AL team while avoiding the first three-game losing skid since opening weekend is something that a first-place team should aspire to achieve. And with the Yankees (winners of eight of their last 10 games) suddenly hot on Boston’s heels, the Red Sox won’t want to give away the top spot in the East so easily.

READ MORE: Wednesday's Child: 13-Year-Old Khary

Tuesday’s loss was marked by timely hitting from Oakland and almost no hitting at all from Boston. Chris Bassitt limited the Red Sox to two runs over seven innings, striking out 10 and allowing just three hits with no walks. It was unquestionably the best start of the season for the 32-year-old right-hander. The Red Sox did have a chance to tie the game — or perhaps win it — in the ninth inning, after a leadoff walk from Alex Verdugo, a one-out walk by Xander Bogaerts, and a fielder’s choice from Rafael Devers that moved the tying run to third base with two outs. Christian Vazquez, though, popped out in foul ground to end the game. The Red Sox finished with just four hits and two runs.

“We’re gonna go through stretches,” manager Alex Cora said. “And we had the tying run at third, the winning run at first on a night that we didn’t too much offensively. So we’ll take that and get ready for [Wednesday].”

The Red Sox may find some relief in that department on Wednesday, when they’ll face James Kaprielian. The 27-year-old will be making his 2021 debut, after he pitched 3.2 innings (allowing three earned runs) in his first two MLB appearances last season. Kaprielian allowed two earned runs on eight hits with one walk in his lone Triple-A start this season, so facing MLB’s best offense won’t exactly be a soft landing for the prospect.

Kaprielian will be opposed by Eduardo Rodriguez, who’s 5-0 with a 3.82 ERA on the season but has lasted just five innings in four of his six starts, including his most recent two outings.

In Thursday’s finale, it’ll be Sean Manaea (3-1, 3.07 ERA) vs. Garrett Richards, who struggled mightily in his last Fenway start. But in three road starts since, he’s gone 2-0 with a 2.84 ERA and 1.105 WHIP.

The Red Sox will welcome in the 16-19 Angels over the weekend, thus giving them a chance to make up for any lost ground vs. Oakland. But for the next two nights, the Red Sox will at least have an opportunity to see what they’re made of when facing some adversity — even if some of that is slightly manufactured at this point in the season.

MORE NEWS: UMass Lowell Closed Due To 'Possible Cybersecurity Incident'

“I mean, our offense is the best in the league. For [the A’s] to go out there and shut us down, that’s good for them,” Tuesday’s starter, Nate Eovaldi said. “We’ve got two more games coming in, so we’ll go out there and get ’em tomorrow.”