Tigers starting pitcher Justin Verlander ended his simulated game early yesterday because of shoulder fatigue.

Photo by Stacy Revere/Getty Images

Verlander threw 45 pitches over three innings and said it was not pain, but fatigue from not throwing which cut his session short. Earlier this week, manager Brad Ausmus said he expected him to throw at least 60 pitches over four simulated innings.   Tigers’ reliever Joe Nathan is making progress as expected. Brad Ausmus also expects that he will return to his role as closer once he's healthy. Nathan did some long tossing in the outfield atPNCParkon Wednesday afternoon and felt good afterward.

What's a "simulated game"?

In a simulated game, two or three hitters take turns in live at-bats against a pair of pitchers. Usually, it's a pitcher recovering from an injury, like Verlander.  The second pitcher is usually a healthy teammate or coach.   There are rarely any players out in the field, and there's no umpire behind home plate. Either the bullpen catcher or the pitching coach will call balls and strikes and determine what "happens" when one of the hitters puts the ball in play.  If it's a hard line drive, they might say it's a "hit"; a weak grounder would be deemed an "out."  After the pitcher retires the side, so to speak, they sit down and rest while the second pitcher goes an inning.

Verlander has been sidelined since late last month with a triceps strain. Reliever Bruce Rondon, who is dealing with tendinitis, remains on the DL. Closer Joe Nathan, also on the disabled list, is still receiving treatment for a right elbow flexor strain.