He certainly took off with it Saturday.
With three appearances in Detroit's six games, Robertson is tied for the lead on the Tigers and tops the club in relief innings. But it's his Saturday appearance in particular that showed his potential value on this staff.
After Justin Verlander's 97 pitches through five innings forced Leyland to go to his bullpen, Robertson came in for back-to-back left-handed hitters to start the sixth. Robertson not only stayed in for two innings, he retired all six batters he faced, including three right-handed hitters in the seventh.
In the meantime, the Tigers took the lead in the bottom of the sixth, putting Robertson in line for the victory.
"We all know the situation with Nate disappointed" him over not getting a starting job, Leyland said. "But at the same time, to me, what he did today is as good as somebody giving you five innings as a starter. You have a one-run game, and he went through it and got us two innings. That's a heckuva contribution.
"That's what you try to impress upon your pitchers. Everybody down there is going to have to do a job if we're going to be good. There's no such thing as mop-up outs and all that junk. That doesn't happen. The importance of that kind of stuff is huge, and I was thrilled."
To call Robertson thrilled about relieving might still be a bit much, but he knows the value.
"This is my assignment," Robertson said. "My whole thing was to give me a couple days to deal with it and then move on. And now this is what I'm doing. I prepare myself in a different way. That's how I look at it."
While the disappointment of not making the rotation seems to have dissipated, his pitches seem to be improving. His fastball, which had been in the mid-to-upper 80s during his Spring Training bid for a starting job, topped 90 mph on Thursday at Toronto, though it slipped back Saturday. His slider, meanwhile, consistently has more movement than it did in his final Spring Training start.
"The one thing, and I said this at the end of spring, my slider's back, and it's got really got really good bite right now," Robertson said.
That was the work in progress for when when he came to Spring Training, and the reason he changed his offseason workout routine to gain some flexibility. Whether a shift to shorter outings with more intensity is making a difference, or whether Robertson's thumb injury has healed enough to gain some of his previous stuff there, is a good question.
"In Spring Training, it was coming around real nice," Robertson said. "The setback for me was when I took the ball off my thumb, because I was feeling really comfortable with everything [up to that point]. But now that I'm at the tail end of this situation, and the two outings that I've come out of the 'pen, it's been really, really sharp."
Add a nasty, biting slider with a fastball that has a little more life on it, and you have the makings of a potentially effective reliever. He still throws his changeup on occasion, because he doesn't want to be a two-pitch hurler, even in relief.
Because of his history, his appeal as a long reliever is obvious. Still, that hasn't been his role so far. If the slider keeps working for him, he's a viable option against left-handed hitters in the middle to late innings, freeing up Bobby Seay for more late-game situations. Saturday was a perfect example.
In a bullpen where Leyland said he's still trying to sort out what to do in the seventh and eighth innings, Robertson is an intriguing piece.
"He can do a lot of different things for you," Leyland said. "He can pitch long. He can get a lefty for you. He's a very valuable piece for you."
It's a role that Robertson can see, and he's preparing himself to fill it. In the process, he's arguably proving himself as a pitcher.
"Obviously, he was somewhat vocal in how he was disappointed to go to the bullpen," Verlander said, "and I think he's going out there and trying to prove something. There's nothing wrong with that. He's going out there and showing he can get guys out. I think it might've lit a fire."
Asked if he had something to prove, Robertson turned the question around.
"Well, I think we all do," he said. "It's not just me. This team's got something to prove."