Watson got the job by overcoming a rocky Spring Training start to surrender only two runs in his last six innings. Both lefties performed promisingly in trials in Pittsburgh last summer, but Watson's stuff is perceived to be a little more reliable, even if Huntington practically said Moskos can rely on coming up at some point this season.
"We are going to need more than 12 pitchers this year and more than 13 position players," Huntington said. "Go master your trade and earn your way back to the big leagues when we have that need. It's not a matter of if, but of when.
"The better we get, the later the decisions come, the more difficult they are and have been. That's a positive side for us, but it's always difficult to tell a young man he is not making a Major League team. Danny took it as well as you can hope.
"Do we need another shorter option guy? A guy capable of going some length? Right, left, how does the bullpen all fit together? That was out of Danny's control. Obviously he got people out this spring. And we expect he will be one of the guys who will get people out for us this summer."
Moskos is 25 and not out of time to impress the Pirates. But Watson established more of a track record last season, particularly in his usage for multiple innings, according to Manager Clint Hurdle.
"We took a little longer look at him last year [41 innings to Moskos' 24 1/3]," said Hurdle. "The package is just a little bit sharper.
"But it wasn't so much Tony over Danny. There is another guy we are going to add [Wednesday], so it was basically the skill sets of the other six in front of Danny we could end up with as well.
But the Pirates still think Moskos has some work to do on his pitches to establish more consistency.
"Command the fastball, tighten the breaking ball," said Huntington. "Continue to develop in the areas we have worked with him on.
"Considering it two days before Opening Day and this is one of our last moves, he is not far away. At the same time, we have a lot of arms that aren't far away.
"Our relievers haven't necessarily all gone out and grabbed hold of jobs and not let them go. [Josh] Harrison and [Yamaico] Navarro certainly have [with reserve infield roles]. It's hard to take either one of them off the club, and one of the options we have going forward is 11 [pitchers] and 14 [position players] before we go back to five starters."
The move left the Pirates one over the 25-man limit, with that last decision - either one more reliever or one more position player -- pending Wednesday.
"There are some guys out there on waivers," said Huntington. "I don't think anything is going to happen, but I wouldn't be doing my job if I closed a door to it."
Huntington is open to carrying two lefties, provided that second lefty can get out batters from either side of the plate better than the right-hander competing for that job.
"Clint has been very open in his desire that, in a bullpen-in-a-vacuum, there are a couple lefties, if not three," Huntington said. "The reality is we need to take the right group.
"A good right-hander is better than a bad left-hander or a solid right-hander is better than a mediocre left-hander. We have some right-handers ahead of the left-handers and are not equipped to have a one-hitter left-hander to face one batter a night 60 some times over the course of the season.
"Our starters have to go deeper into games. And we need relievers who are versatile. We like to have left-handers who can get right-handed hitters out. Clint uses the terms placekicker. We are not going to have too many placekickers running around. He needs to have options.
"If one of his relievers can only get one hitter out a night, we need to be better than that."