Matz threw on flat ground on Monday morning

Matz throws a bullpen session during spring training workouts in St. Lucie. Credit: Jasen Vinlove-USA TODAY SportsMets LHP Steven Matz, who has irritation in his left elbow and is having his start skipped, threw on flat ground from 70 feet on Monday morning, according to the team's beat writers.

He threw hard during the session, which was split into roughly three 10-to-15 pitch innings, reports Dave Lennon of Newsday.

Matz said on Sunday that he is not worried about the elbow issue, according to Marc Carig of Newsday.

Matz, who had surgery to remove a bone spur in September and has dealt with elbow and shoulder issues among others since underdoing Tommy John surgery in 2010, was to start…