The San Francisco Giants stole four bases against Noah Syndergaard on Sunday, a trend that is beginning to concern the New York Mets right-hander.

The Cincinnati Reds went 5-for-5 on stolen base attempts against Syndergaard last Monday.

"The last two starts, I haven't felt very comfortable on the mound in terms of mechanically, which is allowing baserunners to get better jumps off me," Syndergaard said. "I'm slower towards home plate. It's just a slight mechanical issue that I'm still trying to work on."

In 24 starts during 2015, opposing runners were 15-for-16 on attempted steals with him on the mound. The pace has picked up this season with runners already 12-for-13 in five outings. Syndergaard said it's "frustrating."

Syndergaard said he is working daily with pitching coach Dan Warthen on getting faster to the plate and that "it all comes off my leg kick. I'm too slow with that and it's causing me to drag a little bit."