The fatherly worries, of course, are there all the time, though mother and son are doing fine. Minutes before he took the field for his first outing of the spring last Friday, Robertson joked, he was sending a text message to see how they were doing.
He's known as a fiery competitor on the mound, but even he notices a difference in himself.
"I'm kind of an intense guy," he said, "and sometimes I think my intensity goes to a level that it doesn't need to. So making this takes a little edge off."
Well before the fatherly perspective, however, came the veteran perspective. He has long since known that he doesn't have to try to make the team every spring anymore. After signing a three-year contract this winter, he doesn't have to worry about long-term security, either.
That's part of why he can look at Tuesday's trio of scoreless innings against the Astros at Osceola County Stadium and kind of shrug. He felt good about what he was doing, but he wasn't going to think for a minute that he was ready for the season to start. The vast majority of his pitches were fastballs, and he limited himself to just one slider, the main pitch in his arsenal, to get an inning-ending strikeout.
"The big thing is my command on the inside [of the strike zone]," he said. "I think it's a little too early to get excited about anything and praise anything. Especially early on in camp, most hitters come in and they're not really overanxious to attack the inside pitch. I'm throwing in there quite a bit and guys are just not comfortable with it. They're looking to get their swings in out over the pitch."
Or as he put it later, "Nobody takes home a trophy for winning the Grapefruit League."
Before he became a dad, he was looking at his career in a different light. Instead of trying to work hard since last fall, he has tried to work smart.
He still isn't completely sure what happened early last season that caused him to break down. He spent a month on the disabled list with a tired arm after failing to retire a batter in an early June meltdown at Texas. He had been dominant for just under two months before that. He had his strong points afterwards, averaging six innings a start, but the lost month and Texas start loomed in his statistics.
"In April, it just felt like I could just go out there and get it done," Robertson said. "In May, I was a totally different pitcher. Something happened in May. I just try to look at it as a bad month."
Whatever happened, he's doing what he can to avoid a repeat of it. When the season ended, pitching coach Chuck Hernandez strongly suggested not to do much pitching over the winter, and he checked with Robertson later to make sure he wasn't. The less energy Robertson expended in the winter, the idea went, the more he should have for the dog days of the season.
That was a sea change for Robertson. The previous winter, he worked out like crazy while training in the Detroit area, throwing indoors and lifting despite pitching an extra month with the postseason. Now, he had to cut it back.
In some ways, planning for the birth of his son helped. His life had become so enveloped in his family that he couldn't spend the same amount of time focused on training, though he was still a regular at the gym.
Instead of throwing more than a half-dozen bullpen sessions before Spring Training began, he threw just one. Once he arrived, he bought into the advice from rotation mate Kenny Rogers to not overwork himself in his spring outings. Cut back the effort level to 90 percent, put away the slider for a while and keep matters simple for the first few outings.
For Robertson, that means honing his offspeed pitch while trying to command the inside fastball.
"If you can establish inside command, everything to me goes off of that," Robertson said.
It's something that had been brought to him before, but he never felt comfortable enough in his situation to try it.
"It crept into my mind the last couple years," Robertson said. "But I think this year, especially after the Tigers were great to me and my family with the three-year deal, that brings a lot of peace of mind. With my competitive mind-set in the past, I wanted to go out there and win Spring Training games."
Time will tell if those changes make a difference. Robertson has been one of the Tigers' best workhorses the last few years, despite that DL stint, but his results haven't always been what he'd like. His career splits include a 3.87 ERA before the All-Star break, but a 5.30 ERA after, including an .826 OPS allowed in the second half. He has had more than his fair share of low-scoring losses and no-decisions, and opponents have hit a miserly .246 in his career no-decisions, but they've hit .332 in his defeats compared with just .226 in his wins, according to research on baseball-reference.com.
Obviously, Robertson would still like to win every time. He's not that laid-back. But these days, he has other things on his mind, too. And this spring, he has no complaints.
"After watching my wife [give birth], I have no right to complain about anything, even fatigue," he said. "I have no place to say anything."