The Royals did not acquire Vin Mazzaro as a precursor to trading Zack Greinke. If anything, the addition of Mazzaro will have a greater impact on the pitching prospects below him than on Greinke’s immediate future.

Mazzaro, 24, gives the Royals a fifth starter to go with fellow right-handers Greinke, Sean O’Sullivan, Luke Hochevar and Kyle Davies. One of the Royals’ motivations for the trade was to avoid rushing their top young left-handed prospects – Mike Montgomery, Danny Duffy, Chris Dwyer and John Lamb.

That group – along with first baseman Eric Hosmer and third baseman Mike Moustakas – represents the Royals’ future. And Royals general manager Dayton Moore is adamant about all of them developing properly.

"We can’t get impatient," Moore said Thursday. "It’s hurt for a long time with our loyal fans. I don’t want to prolong the hurt. But at the same time, we’ve got to be right on these guys, make sure they’re not rushed to the big-league level. I’d rather be two to three months late with them coming to the majors than two to three months early."

Montgomery, Duffy and Lamb all were drafted out of high school, as was lefty Will Smith, another pitching prospect whom the Royals acquired last summer from the Angels in the Alberto Callaspo trade.

Moore said that several high-school draft choices who pitched in the All-Star Game last season all had 400-plus innings in the minors (Jon Lester, Clay Buchholz and Josh Johnson exceeded that total; Phil Hughes and Trevor Cahill did not). Most of the Royals’ young pitchers are in the 200- to 350-inning range.

The larger question with the Royals, of course, is whether they will trade Greinke, clearing the pitcher’s $13.5 million salary for each of the next two seasons while adding to their young core.

The thin market for free-agent starting pitchers should only increase the demand for Greinke, who was 10-14 with a 4.17 ERA last season. The Royals can either trade Greinke this winter or allow him to increase his value in the first half of the 2011 season, while risking that he might get injured.

Virtually every club is likely to check in on Greinke, but trade discussions are in the infancy stages. Greinke can block trades to 15 teams, but the Royals have yet to receive his list of approved clubs.

They also have yet to exchange names with teams on possible deals.

— Ken Rosenthal