SAN DIEGO – When Matt Wisler held the Mets to six hits and one run in eight innings and 88 pitches in his major league debut two months ago, the expectations that many had for the Braves pitching prospect escalated from high to unreasonable.

He has lasted more than six innings just once in 10 subsequent starts, and Wisler is 5-3 with a 4.65 ERA and .305 opponents’ average after giving up two runs in five innings – and 85 pitches — for no decision in Tuesday’s loss to the Padres. The right-hander has 39 strikeouts, 20 walks and eight homers allowed in 62 innings.

It’s easy to forget that Wisler, rated the No. 34 prospect in Baseball America’s preseason Top 100, won’t turn 23 until next month.

It’s also easy for some people to forget that experiencing highs and lows – usually a lot more of the latter – is the norm for pitching prospects at the outset of their big-league careers. Even for most of best prospects, and even for guys who go on to forge Hall of Fame careers.

Take another look at the second paragraph that has Wisler’s stats after 11 starts. Now consider what the Braves’ recently minted Hall of Fame pitching trio did at a similar point of their careers:

John Smoltz: 11 starts, 2-6 record, 5.49 ERA, .277 opponents’ average, 34 strikeouts, 30 walks, nine homers allowed in 57 1/3 innings.

Greg Maddux: 13 games (11 starts), 4-6 record, 5.35 ERA, .312 opponents’ average, 48 strikeouts, 31 walks, four homers allowed in 69 innings.

Tom Glavine: 11 starts, 2-6 record, 5.46 ERA, .280 opponents’ average, 27 strikeouts, 38 walks, six homers allowed in 62 2/3 innings.

And so, Wisler’s overall stats at the same stage are comparable, if not better, than three of the greatest pitchers in Braves history. Which is not to say that he will have a career comparable to theirs, but simply to point out that not only is it less-than-alarming for a top-rated pitching prospect to struggle early, it’s common.

Not that Wisler is looking at it that way. He wants to be as good as he can be, as soon as he can be. But he seems to have the right perspective.

“It’s all part of the learning process,” Wisler said Wednesday. “For me right now, it’s getting back to being aggressive, finishing my pitches, getting them in the zone. My biggest problem right now is I’m falling behind guys. Guys are battling and I’m throwing six-pitch at-bats every time, so I’m not getting through six, seven innings easy, I have to work hard. The first two innings (Tuesday) I threw 25 pitches each inning. That can’t happen.

“ I’ve got to start having some easier innings, getting deeper in games, saving our bullpen a little bit.”

That’s what he did in his debut. But he’s a bright guy and knows the Mets also had a part in that 88-pitch, eight-inning success for the rookie.

“I pounded the zone in that game,” he said. “They were swinging early too, being aggressive. Luckily I was getting balls in play right at people. So, I mean, I just want to get back to that, trust my stuff. I feel like if it’s in the zone, I can get outs.”

Last week, Smoltz talked to a group of Braves pitchers at Turner Field. Wisler was among them, and he came away from the session with some tips – including keeping his weight on his back leg longer – and also some general advice about being patient and believing in yourself.

“(Smoltz) said it took him a year-and-a-half to figure out his slider, now to throw it for a strike — and he had an unbelievable slider,” Wisler said. “So it’s a learning curve. How to command your pitches and get a feel for your pitches. He talked about his (between-starts) bullpens, what he would do, what he would focus on, trying to work on stuff, getting a feel. He said it took him, like, three years to kind of really figure out what he was doing out there.

“So, obviously having him there to talk to, and talk to (pitching coach) Roger (McDowell), hopefully I can get through that instead of in three years, cut it down to a year or so to figure it out,” Wisler said, smiling. “Just getting it down as quickly as possible.”