The Red Sox were pleased with the development of numerous prospects during the 2007 season, especially Dustin Pedroia and Jacoby Ellsbury. Both players made significant contributions to Boston’s world championship run, but they weren’t the only ones who impressed management.

Enter Jed Lowrie, an infielder, and Justin Masterson, a pitcher.

Both enjoyed success in 2007, but there’s still plenty of developmental work that needs to be done before they can say they have exceeded the organization’s expectations.

Lowrie proved that he possesses solid skills. But there was a strength issue. That’s something he said he focused on last season, and he continues to do so in his offseason workouts. He’s been in Arizona working out with a personal trainer.

Lowrie is considered a solid hitter with good knowledge of the strike zone. When he steps into the batter’s box, he approaches each at-bat with a plan. He is a well-prepared player, and there should be improvement in spring training because of his increased strength.

“I’m continuing to work out and let my body mature,” said Lowrie, a 6-foot, 185-pounder. “I feel like I’m still growing and I feel like I have a lot of potential, but it’s something I need to work at and I’m working at it pretty hard. It’s just a matter of gaining some strength and maintaining my flexibility and range of motion at the same time.”

The 23-year-old, in his third year as a pro, began the 2007 season at Double-A Portland and hit .297 with 49 RBI in 93 games for the Sea Dogs. He was promoted to Pawtucket on July 27 and finished the season hitting .300 for the PawSox, with 21 RBI in 40 games.

Defensively, he made tremendous strides at shortstop for the PawSox, and proved to the parent club that he has the ability to play the position at the major-league level. Even though the Red Sox are pleased with his development, it’s a safe bet — barring a trade — that Lowrie will be back with the PawSox in 2008 and likely will play other infield positions.

From the winter meetings in Nashville earlier this month until now, there have been reports that Lowrie and Masterson could be part of a possible deal between the Red Sox and Twins for two-time Cy Young Award-winning pitcher Johan Santana of the Twins. However, Lowrie said he’s preparing for spring training with the Red Sox.

“Any time you’re mentioned in the same trade for a pitcher like Johan Santana, you feel pretty humble because he’s one of the best the game has to offer,” said Lowrie. “You get sort of humble when you’re mentioned in that company.”

At the conclusion of last season, the Red Sox sent Lowrie to the Arizona Fall League, where he played for the Mesa Solar Sox. Despite a hand injury that sidelined him for the first week, Lowrie was pleased with his performance. He played shortstop, second base and third base, which was exactly what the Red Sox wanted him to do to become more versatile in the infield.

“I really enjoyed my time out there,” he said. “It was a great experience.”

Masterson spent the majority of last season working on command of his secondary pitches, especially his changeup and sinker. The 6-foot-6, 250-pound right-hander has also shown that he’s mentally tough. He pitched last season at Class-A Lancaster, Calif., where Clear Channel Stadium is a hitter’s paradise because of the wind, which usually blows toward the outfield.

The JetHawks led the California League with 217 home runs last season. Lake Elsinore finished a distant second with 148. So pitching in Lancaster isn’t easy. Still, Masterson posted an 8-5 record and a 4.33 ERA in 17 starts for the JetHawks. In 95 2/3 innings, he allowed only 22 walks and recorded 56 strikeouts. He gave up four homers, and opponents had a .275 batting average.

The 22-year-old was promoted to Double-A Portland, where he continued to have success. Masterson posted a 4-3 record in 10 starts and had a 4.34 ERA for the Sea Dogs. He walked only 18 and struck out 59 in 58 innings. Because of his rapid development, the Red Sox invited him to Fenway Park during the postseason.

If the Red Sox don’t make a trade for Santana, they’ll continue to look to their solid minor-league system for help.

jmcdonal@projo.com