Hultzen, the second overall pick in the 2011 Draft, allowed one hit and two walks in the first inning, but escaped that bases-loaded jam and worked his two frames without damage while striking out four.
Walker, a flame-throwing 20-year-old, zipped through the third and fourth innings with only a walk marring his slate. The live-armed right-hander was hitting 96-97 mph on scouts' radar guns, while striking out two in an efficient 27-pitch outing.
The fact Hultzen worked out of trouble in the first spoke loudly, as did the popping of the catcher's mitt when Walker began firing.
"Danny is much more comfortable here early on than he was last year," said manager Eric Wedge. "That's pretty common for a guy in his second year. When you look at all our young pitchers, they've handled themselves very well. They're throwing the ball over for the most part, pitching to their strengths and they look very comfortable out there, which says a lot for them."
Hultzen waltzed through a perfect inning on just seven pitches -- all strikes -- in his first outing four days earlier against the Padres. This time he got in and out of trouble, needing 28 pitches in the first frame alone, but steadied himself in impressive fashion and struck out three of the last four batters he faced.
"I think I was trying to do a little too much," said the 23-year-old. "I was trying to throw the ball a little too hard and that kind of took me out of my mechanics a little, so that's why I was spraying the ball a little bit. But after I calmed down a little and didn't try to throw too hard or too perfect, it worked a lot better."
And that sort of adjustment is critical, since every pitcher in baseball gets in trouble at times.
"That's something that comes with maturity and experience and just going through something like that," Hultzen said. "A year ago if I'd done the same thing, I'd probably have tried even harder instead of just relaxing and calming down. That does happen pretty often. Pitching is a game of adjustment and it's how quickly you can figure that out."
Walker is more about raw power at this point, his fluid delivery unleashing fastballs with such ease that they jump on hitters quickly at the plate. He's also working on a curveball and changeup, as well as a new wrinkle with a cut fastball, but there's no doubt the heater is what opens eyes at this point.
"I've been working on my fastball command, just trying to get ahead with it and throw strikes," said the youngster from Yucaipa, Calif. "So that worked really well for me today."
Walker dealt with just seven Indians batters in his two innings, and caught Lou Marson and Cord Phelps looking at third strikes.
"He does get it easy," Wedge said of Walker's fastball. "He's big and strong and doesn't try to do too much. I like that as much as anything. He looks relaxed out there. His delivery is pretty clean. So you put all that together and you see the way the ball jumps out of his hand and the life it has at the plate."
Walker said he has shelved the "spike curve" he'd been working on that was thrown with his right index finger digging into the ball.
"I ripped my fingernail the other day, so I went back to my regular curve and that felt really comfortable," he said. "I felt the break was really sharp, so I'm just going to stick with that for now."
Both youngsters set down Indians designated hitter Jason Giambi, who at 42 is more than twice Walker's age. Hultzen struck Giambi out in the first and Walker got him on a grounder to second in the third.
"It's crazy," Hultzen said of facing the five-time All-Star, "but I think I've gotten used to it. Last year I was blown away by some of that kind of stuff. I remember facing Ichiro in a live batting practice and facing Justin Upton in Spring Training, and guys like that you see on TV and watched growing up.
"That blew my mind for a little bit, but that's kind of disappeared. But it's still pretty cool to say, 'That's Jason Giambi.' I remember watching him when I was 9 years old. It is pretty cool, but the awe factor is gone."
Instead, there are many baseball people taking notice now of the Mariners young pitchers, led by Hultzen and Walker. That's a tandem that could be imposing for many years to come. And they're undergoing their journey together, pitching back-to-back Wednesday, then running in the outfield side-by-side before heading together to the dugout to watch for a while before heading to the clubhouse.
"It's awesome," Hultzen said of being in lockstep with Walker. "You never feel alone. I'm not saying I would feel alone if we were all separated, but it is an awesome thing to have somebody who is going through the exact same situation. You can stay with him a lot and talk about situations. It's good to have somebody be there for and with you."