ST. LOUIS — Jason Hammel is pitching like an All-Star again — the way he did as a sign-and-flip guy in 2014 and a rotation anchor for last year’s playoff team — so the question for the Cubs now becomes: Is this sustainable?

Hammel doesn’t look at it that way, not after clearing his head during the offseason, altering his training program and refocusing for a World Series contender. He wants more.

Hammel 2.0 handled the St. Louis Cardinals during Tuesday night’s 12-3 victory at Busch Stadium, working into the eighth inning for the first time this year, allowing only one run and tying his season-high pitch count (103).

“I do feel different,” said Hammel (6-1, 2.17 ERA). “I’m definitely not happy with the walks. I know I can do better, as long as I clean that up. I still think the timing’s off with the delivery that I’ve adapted to now.

“But I’m not thinking that far down the road right now. I’m just going game by game, pitch by pitch. I think that’s going to be the right mentality for me. Instead of: ‘Don’t falter.’

“I’m not a negative thinker anymore. I’m just going to stay positive. We’re going to stay here and now and be present.”

Hammel described his outing as “effectively wild” and joked about his second three-game hitting streak: “Who’s counting?” It also helped that the Cubs built a six-run lead before he threw his first pitch, so manager Joe Maddon wouldn’t be so quick to turn the game over to the bullpen.

Hammel excelled for the Cubs in 2014, going 8-5 with a 2.98 ERA in his first 17 starts before getting packaged with Jeff Samardzija in the Addison Russell blockbuster trade with the Oakland A’s. But Hammel found it difficult to uproot his family midseason and struggled to make a quick adjustment to Oakland, finishing at 2-6 with a 4.26 ERA in the American League.

Hammel got off to another hot start last season (2.86 ERA in 103-plus innings) before a leg injury messed with his mechanics and led to a breakdown after the All-Star break (5.10 ERA in 67 innings).

“I believe it’s sustainable, absolutely,” Maddon said. “The biggest thing, again, is if he knows where his fastball is going, he will pitch deeply into a lot of games, because his ball’s got great movement on it. So there’s a lot of mishits, and also his breaking ball is really good.”

Hammel understands his importance to this team, how carrying this momentum all the way through to the finish line would be huge for the 2016 Cubs.

“I don’t see why not,” catcher David Ross said. “He was our best starter last year in the first half. That says a lot with the group that’s in this room.

“He does a good job of keeping those guys off-balance and making the pitches when he needs to. He just looks a lot more sound mechanically. Even when he gets out of whack, he finds his way back into the count.”