MESA, Ariz. -- A quick glance at the stats page heading into Monday's game showed the D-backs with four stolen bases and three caught stealings this spring.

Cause for concern? Nope, they are right on schedule.

That does not mean the D-backs are hoping for that kind of success rate during regular season, but it is right in line with what they are trying to accomplish this spring: an aggressive mind-set on the bases.

"We need to push it a little more this year," D-backs manager Bob Melvin said.

The D-backs stole 109 bases in 133 attempts, the fifth-highest total in the National League, in 2007, a year in which they won a league-best 90 games and advanced to the NL Championship Series.

Last year, the stolen-base total fell to 58, which ranked 13th in the league. In addition, they were thrown out only one fewer time than the year before. In fairness, the stolen-base total was bound to go down with Eric Byrnes and his 50 steals from the year before on the disabled list for much of the season.

The problem, though, was more than just stolen bases. It was the baserunning as a whole, going first to third on hits and moving up on balls in the dirt, among other things.

So this spring, the D-backs have emphasized being aggressive on the basepaths, and if that means being thrown out stealing or trying to take the extra base, so be it.

"That's the thing about Spring Training. You never know how far you can go until you try it," Melvin said. "That's why you see some mistakes in Spring Training based on guys having to figure out what they can do, so come Opening Day, you're on first base and a guy hits a three-hopper to the right fielder's left, you've got to be able to know if you can make it [to third] or not."

It's an adjustment in mind-set for the players, who have to continually remind themselves to push the envelope.

"You want to expand your comfort zone," right fielder Justin Upton said. "During the season you can't afford the same mistakes, so you tone it back just a little bit, but you're still more aggressive than you were before because your comfort zone is bigger."

Other than stolen-base totals, it is hard to measure the effects of more aggressive baserunning.

"The idea is to put pressure on the defense," center fielder Chris Young said. "You want them to be thinking that you might take the extra base. Maybe that means an outfielder will bobble the ball trying to hurry, because he knows we go first to third a lot. The point is you have to do it a lot in order to get a benefit some of the time."

The emphasis on baserunning is not exactly new. The D-backs worked on it the past two springs. Upton said the team's 20-8 start last year that featured plenty of home runs and extra-base hits may have played a role.

"The way we started out in April, we just thought everyone was going to hit 20 home runs and we were just going to blow people out of the water with the big ball," Upton said. "I think then it was a little tougher for us to get back to it. That's why we did a lot of extra work on it later in the season trying to get the feel back for it. This year I think even if we do start out hot again, hopefully we'll stay aggressive and not lose that."