"I was shocked at how controlled his effort was," Mariners manager Scott Servais said after watching Vieira's first bullpen session on Friday. "This is a kid that has gone from kind of being almost off the map, like literally off our board, to a guy that gets added to the 40-man roster.
"My first reaction was, 'This should be interesting, he's going to try and throw 100 mph.' And he didn't. I think he was coached up very well by our pitching guys. I heard one of the comments was, 'Hey, just throw it down the middle at 95 mph nice and easy.' He's a great kid. I was most impressed by his ability to control his effort."
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Anyone who throws 95 "nice and easy" will certainly get a long look. Though Vieira figures to start the season in Double-A Little Rock after pitching at Class A Advanced Bakersfield last year, it's worth remembering that both Edwin Diaz and Dan Altavilla -- two other hard-throwing righties -- made the jump from Double-A to the Mariners in midseason last year and fared quite well.
Vieira signed with Seattle as a 17-year-old in 2010 and issued 107 walks with 139 strikeouts in 192 1/3 innings with a 5.15 ERA over five seasons of Rookie League and Class A ball. But he credits Bakersfield pitching coach Ethan Katz with helping him flip the switch -- and change his slider grip -- last year, as he posted a 2.84 ERA with 53 strikeouts and just 18 walks in 44 1/3 frames.
"At the beginning of the year, I literally lost command of my fastball and slider," Vieira said. "So my pitching coach, Ethan Katz, helped me a lot. We worked before games with the towel drill and throwing with my slider problem. I tried to be consistent with my motion and everything. Every day I worked hard."
Servais credits Katz as well for his role in the improvement.
"I've known Ethan for a long time, and I know how he is wired," Servais said. "He worked for me over with the Angels. We brought him over here, and [Vieira] was kind of his project. Ethan is really good at that. I think more than anything, he's really good at connecting with the player. He certainly won over Vieira in the adjustments he made.
"Then you start having success, and it just grows from there. I'm really anxious to see how that plays out. Again, he needs a lot more Minor League innings, but it's fun to see."
Vieira is having fun, as well, as he soaks up his new opportunity.
"It's unbelievable and a good experience for me, too," he said. "Because I come here and try to do my best job, you know? It's like you and me right now, let's go."