When Clark signed a two-year contract extension in August of 2005 in the midst of his stellar campaign, many assumed that Jackson might spend a good portion of 2006 toiling for Triple-A Tucson.
Instead, Jackson, who just turned 24, is now the everyday first baseman -- though Clark sees occasional time here and there, such as Monday night's game -- and is justifying the organization's faith in him as a key offensive component for the future.
"He gets a good ball to hit most of the time, can handle the ball anywhere and gets a good long look at it," manager Bob Melvin said.
Though Jackson went 0-for-4 on Sunday against the Cardinals, snapping a 13-game hitting streak, the second longest in the league this season next to a 23-game streak by Atlanta's Edgar Renteria.
"This won't be the first 13-game streak you'll see out of him," Melvin said. "He gives himself a good chance every time up there. He's always going to give you a tough, consistent at-bat, and with his stroke he's going to have plenty of those streaks over the coming years and probably this year as well."
Jackson entered Monday's game hitting .292 in 30 games, with a .372 on-base percentage that ranks second on the team.
It's not surprising because all Jackson has done since being drafted in the first round in the 2003 First-Year Player Draft, is hit .319 at Low-A in 2003, .345 at High-A and .310 at Double-A in 2004, and .354 at Triple-A in 2005, all while walking more than he struck out and ripping doubles all over the field.
The team didn't see a lot of point in letting him continue to dominate Triple-A hurlers, fearing it might stagnate his development, so with Clark in place as an insurance policy, Jackson was given the opportunity and has run with it.
"He's aggressive, he's very aware of his opponent, and the more he plays in the league, the better he's going to know his opponents and how they're going try and go after him," Melvin said. "He's just going to keep getting better and better. We don't want him to change his approach; his approach is what we try to teach around here."
Rehabbing right-hander: Russ Ortiz, who has been on the disabled list since April 24 with a right calf strain, will make a rehab start at Triple-A on Tuesday, throwing about 50-60 pitches.
However, this is not expected to be just a short stay in the Minor Leagues.
"We have it mapped out," Melvin said. "He'll have several starts on the fifth day. There are some mechanical changes we're looking at. We just want to get him out there now that he's healthy and try to take some of these things that we think are going to help him and take it to a level where he back to the Russ Ortiz that we signed, a productive guy in a rotation for a long time.
The other pitcher currently on the disabled list, left-hander Terry Mulholland, is scheduled to throw a simulated game in the next couple of days.
No problems: Melvin reported that there were no problems with outfielder Jeff DaVanon after he started his first game since May 6 on Sunday afternoon. DaVanon had been dealing with a sore back.
"He's better, there's a good chance he'll be in there [on Tuesday]," the manager said. "We're kind of over the hump with him."
That's the way the ball bounces: After committing just 13 errors in their first 34 games, the Diamondbacks made five errors in the three-game series in St. Louis, but the manager doesn't see it as the beginning of a problem. He attributed it to the conditions at the Cardinals' new stadium.
"I thought [the Cardinals] didn't play very well defensively either," Melvin said. "I thought the track was a little rough. It's a good field, the grass is great, but with as much moisture as there was -- they had a lot of the Diamond Dry out there -- you saw a lot of sure-handed guys that weren't sure about the hops they were getting. I don't think it was a trend by any stretch because the home team had a tough time with [the field] too."
The Cardinals made four miscues of their own in the three-game set.
On Deck: The Diamondbacks and Padres do battle again on Tuesday night in the second game of this three-game series among two of the top three teams in the National League West. Orlando Hernandez will face Padres ace Jake Peavy. First pitch is scheduled for 6:40 p.m. MST.