HOUSTON -- Stephen Drew and Justin Upton switched places in the batting order on Tuesday, with Drew batting second and Upton third against Astros ace Roy Oswalt.

Arizona manager A.J. Hinch made the move in an effort to spark Upton, who in his young career has struggled in the first month of the season.

The move worked well for Upton, who hit a third-inning home run to dead center, over Tal's Hill -- more than 436 feet -- off Oswalt to give the D-backs a 1-0 lead. Upton came into Tuesday's game batting .224 with four home runs and 13 RBIs.

"I'd like to see Justin get going. He's trying to do too much," said Hinch. "We're fortunate to have an offense that takes a little bit of pressure off of him. He doesn't have to carry this team."

Drew is hitting .290 with two home runs and 10 RBIs for a team that was leading the National League in home runs (39), runs (153), hits (252), slugging percentage (.475) and OPS (.827) entering Tuesday's action.

Hinch said the 22-year-old Upton, who is in his fourth year with the D-backs, needs to be more patient at the plate.

"He's not panicking by any means, but we expect a lot out of him," said Hinch. "As we approach the middle of May, we'd like to see him get going."

Jackson to begin rehab stint Wednesday

HOUSTON -- D-backs outfielder Conor Jackson was scheduled to join Triple-A Reno on Tuesday to begin a Minor League rehab assignment.

Jackson was placed on the disabled list on April 19 with a right hamstring strain. Jackson was batting .267 in 45 at-bats.

The plan is to have Jackson play at least Wednesday, Thursday and Friday with Reno. Friday's game is at Portland.

"Then we'll take a look after that based on how his legs feel and how his swing is on whether we bring him back for Saturday or Sunday or Monday or beyond," said Arizona manager A.J. Hinch.

Snyder riding errorless streak

HOUSTON -- Coming into Tuesday's game at Houston, Chris Snyder's 215-game errorless streak was the third-longest in Major League history by a catcher.

"Catching is definitely less amounts, you have less chances than your typical infielder," said Snyder in downplaying his accomplishment.

Mike Matheny holds the record by a catcher at 252 errorless games from Aug. 2, 2002, to Aug. 1, 2004, followed by Mike Redmond at 248 errorless games from July 2, 2004, to the present.

Snyder's last error was on Aug. 22, 2007.

Stottlemyre pleased by relief corps

HOUSTON -- After Monday's 9-1 win at Houston, Arizona pitching coach Mel Stottlemyre Jr. was encouraged about the D-backs' bullpen, which entered the series with an ERA over 6.00.

D-backs relievers did not allow a run in four innings in preserving the win for Cesar Valdez on Monday, who was making his big league debut. The trio of Esmerling Vasquez (2 innings), Aaron Heilman (1 inning) and Blaine Boyer (1 inning) did not walk a batter and gave up only three singles.

"For the first time, I saw signs of our guys getting out of their rut they've been in," said Stottlemyre. "We were good the first week [of the season]. We were pounding the zone, and the guys got away from attacking the zone and getting ahead of the hitters, and that carried over from game to game.

"It comes down to getting ahead and pounding the zone. Last night was the first time we've gotten back to that."

Stottlemyre said it's about simplifying things, getting strikes, and from there you have options.

Stottlemyre and Arizona manager A.J. Hinch are both impressed with Vasquez, who entered Tuesday with a 3.12 ERA in 8 2/3 innings.

"He's a guy that has electric stuff," said Stottlemyre. "But if he throws it 100 mph, he's not going to throw it by anybody if it's not in the zone."

Added Hinch: "He has swing-and-miss stuff in the strike zone."

Worth noting

A couple of D-backs Minor Leaguers earned honors recently. Class A South Bend infielder Bobby Borchering was Midwest League Player of the Week after batting.429 (9-for-21) with three home runs last week. Triple-A Reno right-hander Josh Collmenter was Pacific Coast League Pitcher of the Week after throwing seven scoreless innings against Tacoma on Friday. It's the second consecutive weekly honor for Collmenter, who won the California League Pitcher of the Week with Class A Visalia for the week of April 19-25.