For different reasons, the two rookies were rushed to the Major Leagues in 2010, skipping valuable Minor League seasoning.
So for the past two weeks, while teammates have taken a break after a long season, Jansen and Monasterios were at the Dodgers' Camelback Ranch-Glendale compound playing catchup on fundamentals with low-level farmhands in the organization's instructional league.
"Instructional league is a great time to work on this stuff," said Dodgers bullpen coach Ken Howell, who supervised the development program. "It's unusual for big leaguers to be here, but not uncommon. We did it when I played. And you do it here without the tension and pressure of a game. I wish more guys would think about it and fix stuff now instead of trying to in Spring Training. It's hard to do when you're trying to make a team. Two or three weeks here and you get it out of the way. That's a heck of a payoff for me. This is not punishment. It used to be bragging rights to get invited. We have to get back to that."
In Jansen's case, his statistics while a Dodger make him seem a better candidate as a teacher than a student. Converted from a weak-hitting catcher to the mound during the 2009 season, he opened the 2010 season in Class A and ended it closing games in the Major Leagues.
The 23-year-old native of Curacao was called up at the end of July and finished the season 1-0 with a 0.67 ERA and four saves in 25 games, striking out 41 with 15 walks in 27 innings. His ERA was the fourth-lowest by a rookie with a minimum of 25 innings in Major League history. Right-handers hit only .064 off him.
Howell said Jansen is working on holding runners, pickoff throws and refining secondary pitches, the slider and changeup. Another task is to get a better handle on managing the game, and he's using a logical role model.
"Kenley's favorite pitcher is Mariano Rivera, and I wanted Kenley to see how Rivera manages his business," Howell said. "He never comes off the mound. He's always ready to go. I picked Rivera because it's somebody that will hold Kenley's interest. I like the way he's calm during the game; he controls his emotions and his mound presence."
"I didn't think I would be this good this fast, but I'm not there yet," said Jansen, who had only 56 2/3 Minor League innings when he was called up to the Majors. "I'm working on throwing over to first, getting a slide step. I respect the hitters. They will adjust to me, and I have to adjust to them to stay ahead. That's why I'm here. I want to get stronger, get in better shape, learn from Kenny on how to control the game."
The 24-year-old Monasterios had more seasoning as a pitcher coming into this season than Jansen, but with only two games above Class A. Nonetheless, the Dodgers liked what they saw of him in last year's Venezuelan Winter League and arranged a deal to acquire him as a Rule 5 Draft pick, meaning he had to stay in the Major Leagues the entire 2010 season or be offered back to the Phillies.
Although that restriction tied the hands of manager Joe Torre at times, Monasterios remained on the Major League staff as a swingman (3-5, 4.38 ERA overall), realizing more success as a reliever (2.06) than a starter (5.91). For 2011, the club has flexibility in that it can send Monasterios to the Minor Leagues without losing him, although he showed up in Arizona to make sure that doesn't happen.
"They want me to finish my pitches, get extension and work on the mechanics of my curveball," Monasterios said. "They showed me video when I was doing it right. I can feel the difference. When I do it wrong, I can feel it. This year was good, but I can do better. I want to make the team next year. That's why I'm here, and why I'll pitch in Venezuela winter ball."
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.