Zack Wheeler threw 30 pitches during a bullpen session Friday at Marlins Park, but the right-hander remains unsure when he will be able to make his first rehab start in his long recovery from Tommy John surgery. Despite having now thrown multiple sessions, Wheeler — throwing fastballs, curveballs and changeups — hasn’t faced live batters and doesn’t know when he will be ready to do so, remaining cautious in his return following two setbacks this year. Mets pitching coach Dan Warthen estimated Wheeler would make a rehab appearance 10 days after facing live hitting.