"He's getting better every time out," Jackson manager Jim Pankovits said. "He's still only 20 years old, and that's hard to believe."
Walker's control wasn't pin-point, as shown by his four walks and 43 pitches out of the strike zone. But he struck out seven and didn't give up a hit after the second inning, when the Lookouts scored their run off him.
"We got the early lead and I was just trying to pound my fastball in there," said Walker, who hit 98 mph once and was regularly at 95-96 mph. "My arm felt good and I was using my legs, so I was able to keep my velocity."
Walker, who improved to 2-2 with a 1.55 ERA, is now complementing his fastball and curve and a new cutter and developing changeup that he had planned to use a lot against the Lookouts' left-handed hitters. But with the early cushion, he didn't need to use all his pitches.
"I didn't have to mess around and try to trick anyone," Walker said. "I went right after their hitters. I got off to a slow start, but I got stronger as the game went on.
A second-round pick of the Mariners in the 2010 Draft, he hit a wall midway through last season as one of the youngest players in Double-A, finishing 7-10 with a 4.69 ERA. But his start this year could warrant a move up to Triple-A Tacoma at some point soon.
Lee, meanwhile, had his first misstep in an impressive April.
"He'd been pitching very well and easily could have been 4-0," Chattanooga manager Jody Reed said. "He just had one of those nights."
Lee, ranked No. 77 in MLB.com's Top 100 Prospects, retired Jackson in order with a strikeout in the first inning, needing just eight pitches. But things fell apart in the second for the 21-year-old and didn't get better in the third.
Steven Proscia doubled on a fastball leading off the frame, James Jones tripled on another heater and John Hicks hit a curveball for a double. The third run scored on a fielder's choice before Lee got out of the inning.
The Lookouts got one run back off Walker in the bottom of the inning when Gorman Erickson hit a sacrifice fly to drive in J.T. Wise, who had doubled.
The Generals padded their lead with three more runs in the third. Jackson had three hits in the inning and the Lookouts committed two errors, one by Lee.
Now 2-1 with a 2.42 ERA, Lee left after throwing 54 pitches, 34 of them strikes.
"He'd had enough," Reed said. "He was getting his pitches up and they were hitting them. I didn't see any point in keeping him out there."
The Duel: Walker vs. Lee
Zach Lee (L, 2-1)
Taijuan Walker (W, 2-2)
Lee was selected by the Dodgers with the 28th pick of the first round in the 2010 Draft and received a bonus deal worth $5.25 million -- the largest in team history -- to bypass an opportunity to play quarterback at Louisiana State.
The Texas native was promoted to Chattanooga midway through last season and finished the year 6-6 with a 4.39 ERA in 25 starts for Class A Advanced Rancho Cucamonga and the Lookouts.
"We go back to the Midwest League together," Walker said. "He's a good pitcher, he just wasn't at his best this time. But I don't really think about who I'm pitching against. I'm just trying to get the hitters out."
Walker was able to do that. Lee wasn't this time. So much for anything being a near cinch in baseball.
Guy Curtright is a contributor to MLB.com.
This story was not subject to the approval of the National Association of Professional Baseball Leagues or its clubs.