What those two deals mean won't be clear for at least a while. Despite getting Miller, Cashman left open the possibility of re-signing closer David Robertson.
Can you imagine a bullpen with Dellin Betances, Miller and Robertson lined up at the end of games? With Adam Warren possibly back in relief and with newly acquired lefty Justin Wilson and others, the Yankees could have a monstrous relief corps.
The Yanks have been decent in a lot of different ways the last couple of years, but they haven't really been dominant in a single area.
Some of that is a byproduct of age and injuries. Some of it is the natural evolution of a roster.
Anyway, Cashman downplayed Miller and Gregorius as simply another couple of steps toward Opening Day. While the Red Sox and Blue Jays have made a flurry of moves, the Yankees had been relatively quiet until Friday.
"We've been trying to get stuff done all winter," Cashman said. "At least today, we were able to push through two things."
Cashman still has starting pitching on his shopping list. He might add an infielder as well, either to play second or third. Or Martin Prado might shift from second to third and allow a pair of kids, Jose Pirela and Rob Refsnyder, to compete for the second-base job.
But Friday was important for a couple of reasons. First, the Yankees can go play with the roster they have right now. No matter how much more Cashman does in the offseason, the Yankees probably need healthy, productive seasons from Carlos Beltran, Mark Teixeira and others to be competitive. This is an unknown quantity that may not be answered until July and August as they push through the grind of a long season. Until Friday, the holes at shortstop and the back of the bullpen were glaring. No more.
There's a larger storyline here, too. In the last year, the Yankees have changed seven of their nine lineup spots. Only Teixeira and left fielder Brett Gardner remain from the 2013 season.
Since then, Cashman has reshaped his club through a series of trades and free-agent signings that brought Jacoby Ellsbury, Brian McCann, Beltran, Prado, Chris Young and Gregorius to the Bronx.
Cashman also acquired third baseman Chase Headley last summer, but has so far not re-signed him. He also has Alex Rodriguez back from suspension, but Cashman said he has no idea what A-Rod's capable of.
With Derek Jeter having joined Mariano Rivera, Jorge Posada, Andy Pettitte and others in retirement, the Yankees will have a different look and feel. As long as Jeter was around, there was still a connection to those teams that went to the postseason 17 times in 18 seasons and won five World Series championships.
Now having missed the playoffs two years in a row, the Yankees are beginning a new era. Until Friday, they didn't know who would replace Jeter at shortstop. Now they do. Sort of.
Gregorius was acquired in a three-team trade, with right-hander Shane Greene going to the Tigers and pitcher Robbie Ray and shortstop Domingo Leyba joining the D-backs.
Gregorius, a career .184 hitter against left-handed pitching, might share the position with Brendan Ryan for a while. Given that Gregorius is only 25 and that he's a premier defensive player already, and that the Yankees gave up young starter Greene to get him, Cashman hopes he'll eventually be the everyday guy.
"He's an exciting talent," Cashman said. "He's an unfinished product."
He's also Jeter's replacement.
"Derek Jeter," he said. "He's a one-in-a-billion."
Gregorius has nice range and good instincts and a big-time arm. At times, he will dazzle. Beyond that, he will make the plays a starting Major League shortstop is supposed to make, and if you ask a dozen Major League managers what they want from that position, this is it.
That is, don't give outs away, extend innings or unnecessarily run up pitch counts. These are the things that lose games.
As for Robertson, his decision may come down to whether he wants to wear the pinstripes again, perhaps for a little less money than he could get to be part of a rebuilding process in Houston.
As for starting pitching, Cashman seems content to wade through the market since there are plenty of attractive options still out there.
Are the Yankees good enough to contend with what they have right now? Possibly.
"I will gravitate toward whatever presents itself as the most realistic option," Cashman said.
Richard Justice is a columnist for MLB.com. Read his blog, Justice4U. This story was not subject to the approval of Major League Baseball or its clubs.