Tim Lincecum averaged just 90.6 mph in his first start of the season, nearly three mph below his career average and well below his mark for 2011.
The right-hander also didn't throw a slider for the Giants, a pitch that places too much strain on his elbow.
He surrendered five runs to the Diamondbacks in less than six innings before he was pulled.
Lincecum's Velocity Way Down, Struggles Without Slider