Like many pitchers, Simon Castro is very, very close to being right where he needs to be. When he has his best stuff, he can look untouchable. When he doesn't, well, he can look a bit like something else.
Also like many pitchers who appear to be on the cusp of putting it all together, it's hard to say whether he'll have his best stuff or something else on any given night.
On Saturday night, he gave Triple-A Charlotte his best stuff.
Castro allowed two hits and struck out six over seven scoreless frames as the Knights outlasted the Toledo Mud Hens, 2-1, in 13 innings.
In two of his last three starts, the White Sox No. 15 prospect has flashed that kind of stuff. Against Gwinnett on April 22, he allowed one run on three hits over six innings. Facing Scranton/Wilkes-Barre a week later, however, he lasted 4 1/3 frames and was charged with four runs on eight hits.
Charlotte pitching coach Richard Dotson said the key for Castro was cutting down on a turn that he sometimes incorporates into his delivery.
"He did a good job getting ahead. He's been pretty consistent out of the stretch and his delivery was real clean tonight," said Dotson, who spent most of his 12-year Major League career with the White Sox. "He sometimes gets a turn out of the wind-up. A lot of times, when guys get too much of a turn, they come out of that turn getting side-to-side, which drops their arm angle, gets the ball flat. It tails instead of sinks, so you try to minimize and simplify the delivery.
"Two out of the last three starts he's made, he's been good with his delivery. It definitely seems like it's making a big difference. The one in the middle of those two starts, he did something a bit different and I got on him after it. He came out today and did it right and it was good."
Castro's always flashed good raw stuff since signing with the Padres in 2006 as a free agent out of the Dominican Republic. With a fastball that can run in the high 90s and a good slider, he led the Midwest League with 157 strikeouts over 140 1/3 innings for Class A Fort Wayne in 2009. A year later, he finished second in the Texas Leauge with a 2.92 ERA for Double-A San Antonio.
Castro had an injury-plagued season in 2011, then was traded to Chicago in the deal that sent Carlos Quentin to San Diego.
The 25-year-old was solid for Double-A Birmingham in 15 starts, then made five trips to the hill for Charlotte last season. Overall, he had a 3.85 ERA with 88 strikeouts and 27 walks in 117 innings.
Now the objective for Castro -- and Dotson -- is to get the right-hander to perform in every start like he did against Toledo and Gwinnett, and not like he did in allowing 17 runs over 21 1/3 innings in his other four outings this spring.
"I think once he gets [the delivery] mastered and we can give him a game plan he can execute, then you have better command and the consistency will definitely help him contribute for us in the big leagues," Dotson said.
On Saturday, Brandon Short supplied both runs for the Knights, breaking a scoreless tie with an RBI triple in the ninth and doubling home Josh Phegley in the 13th. The veteran outfielder came within a home run of hitting for the cycle.
Phegley, Chicago's 16th-ranked prospect, went 3-for-6 a night after homering twice and driving in four runs.