Gwynn Taking Charge : Baseball: His bat, strong performance by Bruce Hurst leads the Padres past the Houston Astros, 3-2.

Everyone knows about the four batting titles. Silver Slugger awards line his trophy case. When you’re considered the finest pure hitter in all of baseball, there are few secrets left to be exposed.

Then again, there’s something mythical about Padre right fielder Tony Gwynn, and other National League teams are damned if they can figure it out.

Gwynn, infamous for being lethal with his barrage of slap singles, has unveiled a new weapon in his arsenal. It’s called the home run. And he’s using it to become one of the best clutch hitters in the game.

Gwynn’s seventh-inning solo homer Monday lifted the Padres to a 3-2 victory over the Houston Astros, extinguishing the Padres’ three-game losing streak in front of a crowd of 11,248 at San Diego Jack Murphy Stadium.

Failing to hit more than four home runs in a season since 1988, he now has four in the past month. In case anyone forgot, he somehow is managing to do this with a broken index finger on his right hand.

“A lot of teams are pitching me inside because of it,” Gwynn said. “I finally said, ‘If they’re going to pitch me inside, forget it. I’ll turn on it and see what happens.’ ”

What happened was that Gwynn slammed a 1-and-1 slider off Astro starter Pete Harnisch some 398 feet away into the right-field seats.

“I still don’t know how I hit it,” said Gwynn, who entered the game hitless in nine career at-bats against Harnisch, “but I’ll take it. I still haven’t seen the ball off him yet.”

Gwynn’s homer was the latest piece of evidence that he has become one of the most feared hitters in the league in pressure situations.

Remarkably, Gwynn is hitting .454 this season in the seventh inning or later when the game’s outcome still is in jeopardy. It’s the highest batting average of any everyday player in the National League.

“I’ve been much more aggressive this year,” Gwynn said, “and it’s paying off. You won’t see a first-pitch fastball get by me. I love those situations, and I think managers hate to see me come up because I put the bat on the ball.

“I’m not trying to do anything different than I normally do in those situations except hack when I see a good pitch. Willie Stargell used to tell me, ‘If you see a pitch real good, and you swing real hard, you’re going to hit the ball hard.”

Gwynn’s homer was all Padre starter Bruce Hurst (6-4) needed to nail down his fourth complete game in his last six starts. Hurst is 5-1 with a 1.94 ERA during that stretch. His latest kept the Padres (30-27) clinging to within 2 1/2 games of the division-leading Cincinnati Reds.

Hurst’s only major transgression of the game was allowing a two-run homer to San Diego native Eric Anthony in the fourth inning. No matter. Padre center fielder Darrin Jackson answered in the bottom of the inning with a two-run homer to left.

It not only was the Padres’ first homer in six games, but that one swing of the bat scored more runs than the Padres mustered in their previous 33 innings against Harnisch (3-6). Harnisch entered the game with a career 2-0 record and 0.30 ERA against the Padres.

Hurst, who’s yielding a meager .194 batting average in the seventh inning or later this season, made sure Harnisch wouldn’t have a second opportunity. He retired 17 of the last 19 batters he faced, preventing the Astros from reaching second base past the fifth inning.

How much faith did Padre Manager Greg Riddoch have in Hurst?

The Padres had the bases loaded in the sixth inning. There were two outs. The game was tied. Hurst still was allowed to hit for himself. He popped up.

Really.

The importance of Hurst’s victory was magnified when the Padres announced that starter Greg Harris would be placed on the 15-day disabled list with back spasms. Harris will miss today’s scheduled start, and the Padres are hopeful he’ll be ready June 16 when he’ll be eligible again.

Gene Harris, who has not started a game since 1989 and never pitched longer than six innings in his career, will replace Greg Harris in the rotation. The roster spot was filled by reliever Larry Andersen, who has not pitched since April 27 when he was hit in the forearm by a line drive from Mariano Duncan from the Philadelphia Phillies.

“We’re almost one-third of the way through the season,” bemoaned Riddoch, “and we still don’t have five starting pitchers yet. We don’t exactly have an abundance of phenoms knocking the door down to take someone’s spot.”

The Padres don’t believe Harris’ injury is serious, but it has been nagging him for the past six weeks. He’s still unsure how it happened but believes it might have occurred when running on the sidewalk one day in late April.

He pitched a complete-game three days later against the Montreal Expos on April 29 but never again has been the same. He went 0-3 with a 10.61 ERA in his next four starts and then changed his pitching mechanics.

“When I was getting shelled,” Harris said, “my back wasn’t bothering me at all. But then I changed my mechanics, and something happened.”

Although Harris pitched 11 scoreless innings in his last two starts, the pain in his back was excruciating. He left after five innings with a 10-0 lead last Sunday in St. Louis, and was forced to fly back to San Diego for examinations. There was no damage to the bone structure, but when the pain wouldn’t subside Saturday night, he was provided a cortisone shot.

“I thought I was going to be OK to go,” Harris said, “but it’s not as well as I’d like. They’re afraid I’m on the borderline of being healthy, and they don’t risk me having a major setback.

“Really, it’s just a freak thing. I still think I can get in 200 innings this year. The biggest problem is just getting rid of the inflammation.”

The Padres also are bracing themselves for the possible loss of third baseman Gary Sheffield for a couple days. He has been playing with a swollen index finger which has left him in a six-for-33 (.182) slump. He conceded that it might be best for all involved if he sat out a few games.

“I just can’t generate any bat speed with it,” Sheffield said. “I keep wondering when is it going to end. But every time I start feeling good, I hit one off the end of the bat and I’m back to square one.”