Nearly a year ago, Brayan Bello pitched a seven-inning no hitter for the Portland Sea Dogs at Hadlock Field. Later in the season, he looked impressive while pitching for the Red Sox. But after two starts with Boston this season, Bello has been demoted to Triple-A Worcester. AP Photo/Michael Dwyer

The Boston Red Sox wrap up their longest streak of the season without a day off on Thursday, when they will have completed a 19-day stretch of games with a three-game series in Baltimore. After a day off, they are scheduled to play 10 games in the following 10 days, meaning they will have played 29 games in 30 days when they finish the first week of May.

It’s a busy time, especially for pitchers. Which is why Manager Alex Cora briefly employed a six-man rotation. It’s something he has resisted in the past, but the combination of hectic schedule and pitchers recovering from injuries forced him to take that approach.

Putting an extra pitcher into the rotation lightens the workload for pitchers coming back from injuries. It also adds pressure on young pitchers trying to prove themselves.

Nick Pivetta, Garrett Whitlock, Tanner Houck and Brayan Bello essentially have been taking part in auditions at the big-league level. The results have been inconsistent, and one or more of them could move to the bullpen.

It’s highly doubtful Chris Sale or Corey Kluber will become a reliever. Each has a long history as a starter and is unlikely to move out of that role if healthy.

Bello is a month shy of his 24th birthday and dazzled with a 1.65 ERA in five September starts last season. All but two of his 79 minor-league appearances have been as a starter, and it seems pretty clear that his greatest value is as a young arm that can be part of the rotation for years to come.

On Sunday Bello gave us another glimpse of what he can be, keeping the Brewers scoreless through the first three innings before Brian Anderson took him deep in the fourth. The Brewers added two runs an inning later and Bello was gone before the end of the inning.

Bello has yet to show he can go deep consistently enough to keep his spot in the rotation. On Monday, the Red Sox optioned him to Triple-A Worcester.

That essentially leaves three other pitchers trying to prove can remain starters rather than pitch out of the bullpen. All three have filled both roles in the past. Houck and Whitlock have each made more appearances in relief than they have as a starter. And each has been more effective in a limited bullpen role.

Houck has a 2.68 career ERA as a reliever, compared to a 3.41 ERA as a starter. Whitlock has a 2.24 career ERA as a reliever and a 4.75 ERA as a starter. Like Houck, his opponents’ OPS (on base plus slugging percentage) goes up considerably each time through the order.

Pivetta is a little different. He has pitched far more times as a starter, with 140 career starts compared to 22 relief appearances. His numbers – ERA, batting average and OPS against – are much better in a starting role.

Yet Red Sox fans remember his appearance against the Rays in Game 3 of the 2021 American League playoffs when he threw four scoreless innings in relief, striking out seven along the way. He was emotional on the mound, feeding off the energy of the Fenway crowd and using it to his advantage.

Cora will have to make a decision. And it won’t be easy. Complicating things further are the ongoing struggles of Kluber, who has an 8.50 ERA through four starts. If he struggles again in Baltimore on Tuesday the Sox may need to pull him from the rotation. Perhaps there’s an underlying injury we don’t know about.

The offense has helped Boston survive the first month of the season. It was on display again in a nine-run eighth inning Sunday in Milwaukee. But the Sox will need to shore up the rotation to remain even on the cusp of the playoff race. Finding the right five men to fill that rotation has been the challenge since spring training began in February. And it’s just as challenging as we approach May.

Tom Caron is a studio host for the Red Sox broadcast on NESN. His column appears in the Portland Press Herald on Tuesdays.