Mariners top prospect Taijuan Walker was promoted to Triple-A Tacoma on Friday and is expected to make his Pacific Coast League debut on Tuesday against Fresno.
Walker, who was 4-7 with a 2.46 ERA in 14 starts for Double-A Jackson, learned of the promotion on Friday afternoon, a day after he recorded a career-high 12 strikeouts over 6 2/3 innings to beat Mobile.
"It was awesome," Walker said. "Awesome feeling to finally get that call. I've been working hard, busting my butt."
The 12-strikeout effort only helped his cause, although the 20-year-old right-hander -- MLB.com's No. 5 overall prospect -- has been particularly good the past few weeks. He's allowed two earned runs or fewer in each of his last five starts while fanning six or more in four of them.
Mariners general manager Jack Zduriencik said the move was well-deserved.
"We feel that Taijuan has accomplished his goals at Double-A and it is time for the next step in his career," he said in a statement. "He is a very hard worker and has tremendous talent. We are looking forward to watching his development continue."
Walker, who ranks sixth in Jackson history with 39 starts, said he's thrilled for the opportunity.
"I'm excited, excited to make the jump, face a new challenge," he said. "But at the same time, there's still one more goal ahead of me. I want to get up there, keep working and make the jump to the big leagues."
Walker, selected 43rd overall in the 2010 Draft out of Yucaipa (Calif.) High School, spent all of last season with the Generals and went 7-10 with a 4.69 ERA and 118 strikeouts over 126 2/3 innings. In 2011, his first full season in the Minors, he was 6-5 with a 2.89 ERA in 18 starts for Class A Clinton.
The 2012 Futures Game All-Star said he was a little disappointed coming out of Spring Training, when the Mariners opted to send him back to the Southern League, a move that only made him focus harder on earning a trip north.
"I've been really working hard this year, ever since they told me I was going down. I was a little bummed about it, but I wanted to get out of here quick," Walker said. "I knew what I had to do and I focused on the things I had to do, just worked at it. I'm glad I got to be here, it's been fun the last two years."
On Thursday night, Walker threw 98 pitches and snapped a streak of seven straight starts without a win.
"It's up there with one of my best games," he said. "I've been in a pretty good groove lately. Hopefully, I can keep it going."
Walker likely will face the Giants' top affiliate on Tuesday at Cheney Stadium.
"Nothing changes, still the same game, go up there and keep everything the same," Walker said of his transition to the PCL. "Right now, everything will stay the same. If I have to make some adjustments, I will."
Walker is one of a handful of elite prospects making his way through the Mariners system. The club already has promoted catcher Mike Zunino (No. 3) and infielder Nick Franklin (No. 4), while left-hander Danny Hultzen (No. 2), the second overall pick in the 2011 Draft, pitched well at Tacoma before suffering a strained left rotator cuff. The Rainiers' rotation also features Mariners No. 5 prospect James Paxton, a 2010 fourth-rounder and two-time MiLB.com organization All-Star.