Presented here are the top 10 pitcher game scores from weekend series, May 18-20, by pitchers who appear in the 2012 Baseball America Prospect Handbook.

• By Minor League Baseball's accounting, Padres righty Donn Roach leads all pitchers with a 5.1 groundout-to-airout ratio. (If his name sounds familiar it's because he was the pitcher acquired by San Diego when they dealt Ernesto Frieri to the Angels.) The 22-year-old has been nothing short of sensational in the high Class A California League this season, going 7-0, 1.69 with a 0.90 WHIP and 47-to-7 strikeout-to-walk ratio for Lake Elsinore. If not for Bakersfield lefty Tony Cingrani, then Roach would lead the Cal League in both ERA and WHIP.

• Scouts are always wary of a pitcher dominating the lower levels of the minors with command and a great changeup. That's the scouting report for David Holmberg, but he also has a sometimes plus fastball and a solid curveball, so there is reason to think he'll keep this up at higher levels.

• Trevor Bauer's Triple-A debut couldn't have gone much better. Since his awful outing on May 1, Bauer has allowed one earned run in 22 innings pitched. Whenever the Diamondbacks have a need at the big league level, Bauer appears ready to step up.

• Julio Rodriguez was considered the fifth Beatle in the Clearwater rotation last year, but while he didn't have the prospect pedigree of some of his teammates, he put up some of the best numbers. He's keeping it up this year in Double-A, as this weekend's start lowered his ERA to 1.88 in eight starts.

Top Performance By A Prospect-Eligible Pitcher Outside His Team's Top 30

Rangers righty Nick Tepesch dealt 7 1/3 no-hit, no-run innings for high Class A Myrtle Beach on Saturday, doing his part to throw the first no-hitter against the Wilmington Blue Rocks in their 19-year history. He struck out nine and walked four. The 2010 14th-rounder from Missouri signed for $400,000.

Worst Game Score By A Prospect

Astros lefty Dallas Keuchel got lit up for 12 runs on 13 hits in a Saturday start for Triple-A Oklahoma City at Reno. In his previous two starts at home in OKC he had struck out 10, walked one and allowed three runs on 10 hits over 14 2/3 innings.

Bill James' game score calculation (Wikipedia entry) rewards pitchers who work deep into games without allowing many runs or hits while providing extra credit for dominance (strikeouts) and control (few walks).