SAN FRANCISCO -- Chicago Cubs second baseman Addison Russell agrees he has to play better after being called out by his manager over the weekend.

"With aggression comes the good things and the bad things," Russell said Monday afternoon from the Cubs' clubhouse at Oracle Park. "The skill set is there. It's just more the mental side, and slowing the game down on the basepaths would be hugely beneficial for myself."

Russell, 25, had a day to forget on Saturday, as he missed two pop-ups, got thrown out at home on a ground ball, didn't advance to third on a potential wild pitch and subsequently got doubled off second base. It's his issues running the bases that concern Joe Maddon the most.

"He has to straighten some things out," the Cubs manager said Saturday. "He has to. There's no question. We've talked about his baserunning in the past."

Going into Monday's game at San Francisco, Russell had made an out on the bases (not including pick-offs, caught stealing or force-outs) in one of every 41.5 plate appearances. According to ESPN Stats & Information research, that's the second-worst ratio of any player with at least 100 plate appearances this season.

Russell knows where he has to get better.

"You have to know the situation in the game and what the score is," he said. "You have to know where the ball is, too, and where the fielders are playing, as well. You can't be too anxious to get to the next base.

"Being aggressive on the basepaths does have its advantages and also its disadvantages."

Unprompted, Russell acknowledged having other on-field issues over the weekend.

"Also, not missing signs, as well," Russell said. "Stay on top of those. Remind myself, I need to become more familiar with the signs, as well. So there's no gap there. You know exactly what's being put on so you can do your job more efficient."

Asked to be more specific, Russell replied, "At the plate and on the bases. Just being aware ... I haven't played as much as I've liked to play, but it's no excuse for not being in the moment. You have small mistakes like that, and it's definitely something you can be better at. Especially from the mental side."

Informed that Russell admitted to missing signs, Maddon was glad for the accountability but would like the problems fixed.

"We just have to keep talking to him," he said. "We have. We always do ... We have to get him to focus consistently. He seems to do it pretty well on defense."

Maddon was asked why the focus isn't always there.

"You'll have to ask him that," he responded.

Russell has a .730 OPS this season in 53 games after serving the final 28 games of a 40-game suspension issued last season for violating the league's domestic violence policy.