The Cardinals' No. 2 prospect allowed a run on three hits while striking out eight over six innings as Double-A Springfield bested Northwest Arkansas, 8-4.
Martinez walked one and faced four over the minimum for the Cardinals. The 20-year-old right-hander's only mistake came when he gave up a solo homer to Paolo Orlando in the fourth inning.
"He had a swing-and-miss changeup tonight," Springfield pitching coach Bryan Eversgerd said. "His curveball looked good, he threw some good ones and he had three things going. His fastball is always good, he threw some two-seam fastballs that the bottom just fell out of. And when you're throwing 95 [mph], that's tough to get a bat on."
Martinez's strikeout total was the highest since he moved up to the Texas League on June 15. The Dominican native is 3-3 with a 2.94 ERA in 12 starts for the Cardinals and has fanned 52 batters over 64 1/3 innings. Martinez had been winless since July 14, despite not allowing more than three earned runs in five starts.
"One thing when he was in Palm Beach, at times, he would use his secondary pitches a little too much and wouldn't trust his fastball," Eversgerd said. "He's done a nice job pitching off his fastball since he got here and that's something we've worked on with him. When he learns how to use it all effectively and mix it, which he is starting to do, he is going to be fun to watch. In fact, he is fun to watch."
Overall, Martinez is 5-5 with a 2.96 ERA in 20 starts between Class A Advanced Palm Beach and Springfield. While MLB.com's No. 23 prospect isn't likely to see Triple-A this year, it's likely something in the not-too-distant future, based on Eversgerd's praise of him.
"I think it's just a matter of refining his pitches a little bit," Eversgerd said. "His natural stuff gets him out a lot of times. A little bit better command and just executing pitches in certain situations. Stuff-wise, it's electric for sure. He's made progress which is great to see. It's a nice arm and he's fun to watch."
Xavier Scruggs homered twice and drove in five runs while Kolten Wong, St. Louis' No. 4 prospect, tripled home a run for Springfield.
JC Sulbaran, the Royals' No. 6 prospect, took the loss after allowing four runs on four hits over 3 2/3 innings for the Naturals.