"I went through a whole year in the bigs last year," Walker said. "I went through some ups and downs. I felt like I kind of matured on that part, where I can control my emotions a little more."
Walker draws on his experience of pitching at Dodger Stadium on Jackie Robinson Day in front of a full house and a national television audience, when he gave up five runs and walked four in just four innings in a 5-2 loss in his second start.
"Definitely," said the youngster from Yucaipa, Calif. "I got a little excited at times on Jackie Robinson Day and kind of got out of my game. I was overthrowing a little bit, but I've learned from that. I just have to take it in for a second, then refocus and treat it like it's any other game."
First-year skipper Scott Servais said it's a perfect scenario for Walker to make his season debut, envisioning a future where Walker will be called on to make many big starts in his Mariners career.
"I don't have any concerns there at all," Servais said. "I think he'll be juiced up and you'll see a really good fastball. The thing with Taijuan is, the secondary stuff, can he harness it and get in the strike zone and be the complete pitcher and not get locked into one pitch? I'm excited for him to get that opportunity, and I think he's ready for it."
Walker was erratic at times in Spring Training. He didn't post the dominant numbers of a year ago. But then again, Walker's tremendous Cactus League showing in 2015 didn't carry over, as he got off to a bad start in the regular season.
This spring, Walker feels he paced himself better, saved himself for the regular season and learned more about pitching in the process. He knows opposing hitters will sit on his mid-90s fastball until he proves there's something else to worry about.
"That's always going to be the game plan against me until I show I can throw offspeed pitches for strikes," Walker said. "I realized in Spring Training that I needed to have a Plan B, and that Plan B is to pitch backwards. Plan A is always establish the fastball first, but if I need to, I feel pretty comfortable right now with my offspeed pitches."
Walker has been adding a slider to his repertoire in recent weeks, and he will mix that in with his changeup and curve. Many have predicted this to be a breakout season for the young right-hander, and it all begins Friday on what should be a lively stage as Safeco Field fans greet a team that looked good in taking two of three from the defending American League West champion Rangers in the opening series.
"It's going to be fun. It's going to be loud," Walker said. "I've got my mom, brother and sister coming out, so it should be a good one."