Justin Masterson fires a pitch for the PawSox during last night’s game against the Scranton/Wilkes-Barre Yankees. He went six innings, allowing two runs on four hits as he prepares for a possible call-up to Boston.

The Providence Journal / Glenn Osmundson

PAWTUCKET — Before his first Triple-A start last night with the Pawtucket Red Sox, one of the few things PawSox manager Ron Johnson knew about hot prospect Justin Masterson was that his wife baked some great cookies.

“I had some butterscotch-oatmeal. They were unbelievable,” Johnson said of Meryl Masterson’s cooking.

Last night, it was Meryl’s husband who was getting Johnson’s praises after his outing against the Scranton/Wilkes-Barre Yankees.

“I was really impressed,” Johnson said. “It didn’t take more than an inning to see the attraction. He has really good stuff.”

Though the season is still fairly young, Masterson has made starts all over the Red Sox organization. He began the year with Double-A Portland, but made two spot starts for Boston, with the last coming May 20. After that game, in which he got his first major-league win, Masterson was optioned to Pawtucket.

Originally, the 6-foot-6, 250-pound right-hander was told he’d miss a start to get some rest. But when Boston’s Daisuke Matsuzaka suffered an apparent shoulder injury Tuesday night in Seattle, Masterson’s start was moved up two days, to last night.

That puts him on track to pitch again Tuesday, which is when Matsuzaka’s turn in the rotation comes up again.

Before last night’s game, however, Johnson wasn’t letting on as to why Pawtucket had juggled its rotation. Still, signs point to the 23-year-old’s being on the mound when the Red Sox open a three-game home stand against Tampa Bay.

Though he hadn’t pitched in nine days, Masterson was sharp off the bat. He retired the first three Scranton/Wilkes-Barre hitters he faced on only 13 pitches. Johnson said Masterson would be on a 90-pitch count, and that’s exactly what he needed to go six full innings.

In that span, he allowed four hits, two runs (one earned), struck out four, and walked one. He also had a hit batsman and wild pitch. Fifty-nine of his 90 pitches were for strikes.

“I felt great; I’m glad we could get a victory,” Masterson said. “I just wanted to do what I usually do — throw sinkerballs, get ground balls, and I got exactly what I wanted. [Catcher] George [Kottaras] called a great game, and I had a great defense behind me.”

Johnson felt Masterson’s performance looked even better coming against the Yankees, who lead the International League North.

“He got six innings against probably the best team in the league. To me, that magnifies the outing,” Johnson said. “I liked the way he pitched around the error.”

In the fourth inning, with two outs but with men on first and second, Scranton DH Greg Porter’s grounder went between the legs of second baseman Joe Thurston, allowing a run and cutting the score to 3-2 for Pawtucket. But Masterson went right back to work, getting Justin Christian to ground out to third to end the inning.

Jumping from Double-A to the majors as Masterson did isn’t always as big a leap as it seems, Johnson said. When he was managing in Portland, he saw David Pauley and Abe Alvarez through such situations, and said there is generally more good than bad that comes out of it for the player.

Even though his stints with Boston have been short, Masterson has been able to learn a great deal from the Red Sox.

“Like tonight; I hit my spots well. I didn’t think my ball was sinking as well, not as much as I can,” he said. “A lot of it is just trusting what you have and letting what you have work for you. You have to stick with what you know is your game.”

Part of the reason why minor-league pitchers can be successful when asked to fill in for Boston, Johnson said, is because of the quality of person the team looks for during scouting.

“As a whole, the scouting department does a phenomenal job of acquiring people with a similar makeup and mentality. It makes our jobs a lot easier,” he said. “And it’s not a guess. I’ve been in meetings where they’ve spent a lot of time talking about (a player’s) character.”

A young man of great faith — he was born in Kingston, Jamaica, where his father was serving as dean of students at a theological seminary — Masterson seems to fit that mold as well.

And as for Meryl’s cookies, Masterson says she liked to sneak batches into the Portland clubhouse and has enjoyed doing the same with the PawSox. And his favorites are the butterscotch-oatmeal as well, “without a doubt.”

smanza@projo.com