Getting a firsthand look this spring has made a much bigger impression.
''He's nasty,'' Peralta said. ''He's really good. His fastball has really good, heavy sink. It's hard to hit him.''
Peralta, an 11-year veteran, isn't alone in that assessment.
''It's pretty universal,'' Cardinals manager Mike Matheny said. ''Every time he walks off the mound and (our hitters) walk out of the cage, it's, 'Wow! That stuff looked good from the field, but I didn't realize up close what it looked like.'''
Martinez will get the ball on Friday when the Cardinals open their Grapefruit League schedule against Miami, beginning a road that they hope will lead back to the World Series. When Martinez walks to the mound he will be trying to put the events of a trying week behind him.
The 22-year-old Martinez made news this week when a website published the favorite list from his Twitter account, which contained pornographic images and links to adult websites. General manager John Mozeliak indicated that the club thought hackers were at least partially responsible for the content and Martinez apologized.
''I want to acknowledge fault for what happened,'' Martinez said through an interpreter. ''That was my responsibility. I want to apologize to the fans, the organization. I didn't mean to cause a distraction. Obviously, it's something that you don't want to go through, but I accept responsibility, and I'm ready to move on and focus on baseball.''
Considered a candidate for the fifth spot in the rotation, Martinez has a blazing fastball and a good slider. That combination made him a success out of the bullpen late last season and in the playoffs, but he's expected to ultimately move to a starting role, where he took the ball 37 times in the minors over the past two seasons.
''The ball is exploding out of his hand,'' Matheny said. ''He just has a real good presence. You watch him finish his pitching and he is not even breathing hard.''
Martinez's early spring performance takes on even greater importance now that the Cardinals have, at least temporarily, halted the workload of Jaime Garcia. The left-hander, who is coming off shoulder surgery, had been considered the favorite to claim the fifth rotation spot, but shoulder soreness prompted Garcia to get a cortisone injection on Wednesday and he is unlikely to be ready for the start of the season.
That would leave Martinez battling with Joe Kelly, and possibly Tyler Lyons, for the final starting spot.
Should Martinez claim that fifth starter's spot, he'd likely have an innings limit.
''If he ended up winning a starting spot, looking at his past couple years he was in the 125-ish (innings range), trying to say he would be good to go to 200 - I don't think that would be accurate,'' Mozeliak said.