Boston’s top three pitchers from the 2017 draft are being challenged and are struggling.

The quest to develop starting pitching is never ending, for the Boston Red Sox and every other team.

In last year’s amateur draft, Boston chose pitchers with three of its first five picks, committing over $3.6 million in bonus money.

With Boston’s 2018 minor league assignments, the Red Sox showed confidence in the trio – sending the two college pitchers (Tanner Houck and Jake Thompson) to advanced Class A Salem, and high school pitcher Alex Scherff to low Class A Greenville.

“All three guys had good spring trainings,” said Ben Crockett, the Red Sox director of player development. “And all have some impressive stuff and ability to pitch, so we felt like we want to challenge them.”

They are definitely being challenged.

In Salem, Houck has a 5.91 ERA in three starts, with eight strikeouts and 13 walks in 102/3 innings.

Thompson has a 4.43 ERA in four starts (201/3 innings), with 15 strikeouts and seven walks.

Scherff, who did not pitch last season after he was drafted, is finding pro ball rough – 10.22 ERA in three starts, with 10 strikeouts and 10 walks in 121/3 innings.

It’s early and, in the development game, it’s more important how you finish.

“You try to make the right decision for each guy and match his level of stuff and command,” Crockett said. “You try to put them in a place where they will do well – but be challenged.”

Crockett said such a fast track is not unusual. He’s right. Two well-regarded college pitchers, Jonathan Papelbon and Alex Wilson, began their first full season in advanced Class A.

But others – such as Anthony Ranaudo, Brandon Workman and Matt Barnes – did not. Of the seven former college pitchers now starting in Pawtucket and Portland, all but one began at lower Class A Greenville. The other, Portland’s Kevin McAvoy began at Salem.

Some high schools pitchers – Jon Lester, Henry Owens, Trey Ball and Michael Kopech – pitched their first full pro season in Class A.

Clay Buchholz, who was drafted out of junior college, pitched in Greenville and Salem one year, and reached Portland (and the majors) the next.

Not all them had stellar numbers through the minors.

Lester’s ERA rose as he moved up and, when began 2005 in Portland with a 5.68 ERA. Lester did not look like a prospect but settled in to become the Eastern League Pitcher of the year.

Lester is a rare success story for the Red Sox’s hopes of growing their starting rotation. Since Lester was drafted in 2002, only he and Buchholz (2005) became longtime regulars in the Red Sox rotation.

The next draft pick who may eventually make the rotation is Brian Johnson (2012), who is a spot starter while pitching out of the Boston bullpen.

Others became full-time relievers, including Papelbon, one of Boston’s best closers in history.

As Crockett pointed out, Houck, Thomson and Scherff all have “stuff.” Houck looked impressive in spring training, especially when he struck out J.D. Martinez (fastball) and Mookie Betts (curveball) in an intrasquad game.

One side of the argument is that pitchers should be eased in to gain confidence. The other side – which Boston is taking – is that players need to learn how to pitch and the best way is against tougher competition.

SALEM’S ROTATION is interesting because, while it looks like the college kids are being rushed, Thompson (age 23) and Houck (who turns 22 in June) are the oldest Salem starters, ahead of Nicaraguan Roniel Raudes (20) and Venezuelans Darwinzon Hernandez (21) and Bryan Mata (18).

Mata, who turns 19 next month, may be the best. He throws a low 90s fastball with movement, plus a change-up and curve. He has a 2.03 ERA after three starts, but has allowed 13 walks in 131/3 innings.

THE BEST STARTER now in Boston’s system began last year in Portland. Left-hander Jalen Beeks has sizzled in three Triple-A starts with a 0.64 ERA, 26 strikeouts and five walks in 14 innings. High pitch counts limited Beeks to four innings in his first two starts. He finished six innings on Saturday, holding Gwinnett to two hits, striking out 10.

JAY GROOME is considered Boston’s best pitching prospect. He was the 12th overall draft pick in 2016 with a $3.6 million signing bonus. But injuries limited him to 551/3 innings last year (6.70 ERA in 11 Greenville starts, but 58 strikeouts in 44 innings). And Groome, 19, is still in Florida, nursing a mild forearm sprain.

“He’s doing well, progressing,” Crockett said. “Still working on getting back on the mound. Then we’ll have to go through a progression to build up innings.”

Before spring training, we wondered if Groome could reach Portland this summer. I think we can rule that out.

CAN YOU NAME the top four pitchers Boston drafted in 2011? It’s a trick question. After taking Barnes and Owens, the next pitchers turned out to be outfielder Williams Jerez and catcher Jordan Weems. Both have converted to the mound as relievers.

Jerez, a left-hander in his fifth year as a pitcher, is dealing in Pawtucket, allowing no runs and one hit over six innings with six strikeouts.

Jerez’s development may be one reason why Boston felt comfortable trading Roenis Elias on Monday.

Weems turned to pitching midway through the 2016 season. He is in Salem (one run and two hits in 82/3 innings, with 10 strikeouts – but also seven walks).

PAT LIGHT, a 2012 Red Sox draft pick (37th overall) was a starter who turned reliever, reaching Boston in 2016. He was traded to the Twins that year for Fernando Abad. In 2017, he pitched in the minors for the Pirates and Mariners. This year in Triple-A, Light allowed eight earned runs over three appearances and was released by Seattle last week.

Staff Writer Kevin Thomas can be reached at 791-6411 or:

[email protected]

Twitter: @ClearTheBases