As you may have noticed, the Braves have been somewhat of a disaster on the basepaths this year, at least when attempting to steal bases (or hit-and-run, or suicide squeeze). After last night's game, they now have 5 steals versus 10 caught stealings, which is a terrible 33% steal rate. No Brave has more than 1 steal, and every Brave with a SB has been caught at least once.
If you project that rate out for the entire season (hey, we've played 30 games, so that's allowed now, right?), the Braves would have 27 steals versus 54 caught stealings. Since 1980, no team has stolen that few bases in a full season. The 1994 Mets had only 25 SBs (vs 26 CSs, for a 49% steal rate), but that was a strike year. The fewest number of SBs in a full season that I could find was 30, by the 1983 Red Sox (who had a 54% steal rate).
The Braves' current 33% stealing success rate would easily be the lowest since 1980. Several teams have come in at 48%: the 1980 Blue Jays, 1984 Brewers, and 1992 Red Sox. So the Braves need to improve their success rate by 15% just to match the worst rates of the last 30 years.
If anything, these numbers actually understate the Braves' futility, since a few of the plays have been particularly damaging. Most notably, there was the failed suicide squeeze in which Tommy Hanson missed the bunt and Eric Hinske was a dead duck; this decreased the Braves' win probability (WPA) by 17%. Two other CS plays had a WPA of -10% or worse. All told, the Braves' 10 caught stealings have cost the Braves' 60% of a win (-0.60 WPA).
By contrast, the Braves' few successful steals have barely helped the club at all. The 5 stolen-base plays have increased the Braves' win chances by a total of 7%. So the Braves' net WPA on steal attempts (and other plays that result in failed steals) is -0.53. Projected out to the entire season, that'd be -2.86 WPA, which is equivalent to costing the team almost 3 wins.
Examining the game logs, none of the Braves' 5 steals has helped them score a run (Martin Prado scored after his steal, but he would've scored even without it). What's worse, each of the Braves' last 3 caught stealings has been followed by a walk, meaning that the runner could have ended up on 2nd without risking the out.
According to Colin Wyers on Twitter last night, the Braves' baserunning has cost them 8 runs using Equivalent BaseRunning Runs (EqBRR). This is just an estimate, though. Nobody knows for sure how many runs baserunning has cost the team, though steal attempts (and the other plays that involve sending runners) have obviously been a net negative. Perhaps the Braves should just stop running altogether and let the hitters do the work.