ANAHEIM -- The Cardinals' defense, so porous in April, has been much more stable of late, in large part due to improved performance at the shortstop position.

The Cardinals entered Wednesday still atop the Majors with 11 shortstop errors, at least five more than every other team. But only two of those have come this month, and Aledmys Diaz, in particular, has looked much more sure-handed.

After opening his big league career with five errors in 15 games, Diaz had one miscue in his next 15. He's not just making the routine plays now, either. Diaz is piling up the web gems, his latest a sensational play in the hole to help Mike Leake out of first-inning trouble Tuesday in a game the Cardinals went on to win, 8-1, over the Angels.

"He's shown that he has the ability to make some really good plays at short," third baseman Matt Carpenter said of Diaz after the win. "It's in there."

One of the reasons the Cardinals planned to start Diaz in Triple-A this season was to allow him time to fix some mechanical issues the club identified while watching him field in Spring Training. He's since made those adjustments, albeit at the Major League level, with help from coaches David Bell and Bill Mueller.

"He's been able to put himself in position where he just keeps improving, and, overall, the combination of some mechanical adjustments and then having some success and the confidence leads you to be able to make incredible plays like the one he did [Tuesday]," manager Mike Matheny said. "He's starting to be able to show not just more consistency, but pretty good range."

Diaz's defensive improvement isn't isolated. The Cardinals have committed three errors in nine games this month after tallying 24 in as many April games.

Worth noting

• Registration for the seventh-annual Cardinals Care 6K and One Mile Fun Run is open at cardinals.com/6K. The races are scheduled for Sept. 18, with the starting line to be at the Stan Musial statue and the finish inside Busch Stadium. All participants will receive a ticket voucher, T-shirt and medal/ribbon. Those who fundraise for the event will be eligible for additional prizes.

• Right-hander Carlos Martinez threw his bullpen session Wednesday without issue, which keeps him on track to make his scheduled start on Saturday. Martinez exited his start last Friday due to fatigue and hadn't been on the mound since.