The Mets have been hit hard by injuries, but not in their rotation. Consider their starting pitcher options: the four currently in the group; David Peterson, who finds himself in a kind of rotation purgatory ; Sean Manaea; Tobias Myers (if stretched out); a just-optioned Christian Scott; and Jonah Tong, whose swing-and-miss stuff has begun to tick up with Triple-A Syracuse. A team with many issues — including maximizing what is a talented crew of starting pitchers — does not have a depth issue. Which is one more reason Kodai Senga needs to figure himself out quickly. Kodai Senga reacts during his April 17 start for the Mets. IMAGN IMAGES via Reuters Connect The leash cannot be long for Senga, whose turn manager Carlos Mendoza would not guarantee after his last blow-up, although the club decided to give the right-hander another start and a few more days of rest.…