SANTA CLARA—The West Coast heatwave wreaked havoc on the 49ers’ practice schedule this past week, leading coach Kyle Shanahan to joke that he, like his players, will take intravenous fluids to rehydrate. “I still do it, if I had too much fun the night before,” Shanahan said.

The 49ers just blew another 10-point fourth quarter lead and lost 24-23 to the Arizona Cardinals. Now the 49ers are 2-3. Here are their grades for this pathetic performance.

Two weeks after faltering on the road to the Los Angeles Rams, the 49ers blew another 10-point lead and exited with a 24-23 loss to the Arizona Cardinals, who went ahead on Chad Ryland’s 35-yard field goal with 1 1/2 minutes to go. As the Bay Area heat wave continued, temperatures on the field reached nearly 115 degrees.