"He's had a very good spring, quietly," manager Jim Leyland said, "and we're watching him closely."
Ni reported to camp having gained weight from last year, by design. It isn't going to make him a power pitcher, but so far, he's a more consistent hurler with his command. He had allowed a hit and a walk over 3 1/3 spring innings until he gave up a run on a hit and two walks over 1 2/3 innings Monday against the Mets.
One point Leyland wants to see is a more consistent breaking ball to throw against left-handed hitters.
"He's got to have a weapon for a left-hander," Leyland said, "and it's got to be something tempting."
As long as Daniel Schlereth is healthy, he appears to have the inside track for a spot on the team as a lefty specialist. Brad Thomas, too, has a good chance to make the squad, but mainly as a long reliever. The Tigers could take three lefty relievers, especially given their predominantly right-handed pitching rotation.