Five minus one equals four. You don’t need a Ph.D. in analytics to know that. So when Wei-Yin Chen hopped the free-agent ferry down to Miami last month, that officially left the Baltimore Orioles' starting rotation with just four arms. Well, technically, they have eight arms, but if you’re counting only the ones that they throw with, then it’s four. But I digress.

The bottom line is, with two weeks left until pitchers and catchers report, the O’s still haven’t spackled the space created by Chen’s exodus. So unless Buck Showalter secretly plans on going all 1971 and using a four-man rotation, the Birds still need another starter if they stand any chance of competing in the AL Beast. Unfortunately, it’s already a day after Punxsutawney Phil did his thing, and the pickins are slimmer than Hillary Clinton’s margin at the Iowa caucuses.

Here’s a look at who’s out there, and the likelihood of each hurler ending up in Baltimore. In honor of the recent mid-Atlantic blizzard, odds are expressed in relation to a snowball’s chance in hell (scale of 1 to 10 snowballs, with 10 snowballs being most likely).

Yovani Gallardo: The fact that Gallardo is still available is borderline shocking. Yes, his 5.9 strikeouts per nine innings last year marked a career low and his 1.42 WHIP was a career high, but he’s a former All-Star who’s only 29 years old and has made at least 30 starts in each of the last seven seasons. Part of the reason he’s still out there is that the Rangers made him a qualifying offer and he declined it, which means that any team that signs him will be forced to give up a high draft pick. Judging by general manager Dan Duquette’s recent comments, the Orioles -- who need a strong draft like Tim Burton needs Johnny Depp -- would prefer to hold on to the 14th overall pick, thanks very much. Even if their stance on that changes, Gallardo, who earned $14 million last season, likely would be too expensive for Baltimore’s taste. Snowball score: 2

Mat Latos: Like fellow free agent Doug Fister, Latos was one of the game’s more dependable starters until not too long ago. Like Fister, he’s coming off a down year (last season’s 4.95 ERA and 1.31 WHIP were both career highs), has been hampered by injuries recently, and is precisely the kind of thrift-shop thrower that the buy-low Birds typically target. Unlike Fister, whom many thought would land in Charm City but ended up signing with Houston last week, Latos is still available. There are concerns about his attitude after he bad-mouthed Reds management and teammates last winter, but given his résumé and price tag -- he shouldn’t cost much more than the $9.4 million he earned during his forgettable 2015 campaign -- the Orioles might be willing to look past that. Snowball score: 7

Andrew Cashner: If you’re thinking outside the free-agent box on potential trade targets, you’d want to start with guys entering the final year of their contracts, players whose clubs would like to get something in return instead of simply letting them walk nine months from now. Among that group, Cashner makes lots of sense. From the Padres’ perspective, the team is going nowhere fast, so why not try to restock by unloading a marketable asset? From the Orioles' point of view, there’s a lot to like in Cashner: He’s a former first-rounder who can run it up there in the mid-90s. He posted a 1.13 WHIP in 2013, and then again in 2014. And not for nothing, his 2016 salary is a fiscal-friendly $7.15 million. Of course, there’s always a catch. In Cashner’s case, there are two catches. First, his 2015 campaign -- during which his WHIP ballooned to 1.44 and his walk rate increased by almost 50 percent -- featured more red flags than an NFL coach’s challenge clinic. Secondly, in order to make a trade, you actually have to give up something in return, and it’s not like the Orioles’ farm system is teeming with coveted prospects. That said, now that Chris Davis is locked up for seven more years, Baltimore might be willing to part with a young first baseman such as Christian Walker or Trey Mancini. As for whether or not San Diego would be interested, that’s another question. Snowball score: 4

Somebody else: Jeremy Guthrie and Tim Lincecum are among the other names that have been linked to the Orioles, and both make sense to an extent. Guthrie would be a nice story, seeing as how he’s a former Oriole who got his first big break with Baltimore, but he turns 37 in April and the opposition hit an unfathomably high .363 against him last year, the fourth straight season that he’s been roughed up for a batting average against of .323 or higher. As desperate as the O’s are, they’re not that desperate. As for Lincecum, yes, he’s a rebound candidate, but given his $18 million salary last season, it’s hard to imagine him being within Duquette’s price range, even with a discount for recent mediocrity. Snowball score: 3

Nobody: As impossible as it seemed three months ago that the Orioles would acquire zero staring pitchers this offseason, it’s now a very real possibility. If that’s the case, then Chen’s replacement will come from within, as unsexy as the idea might be. Mike Wright was recently ranked the franchise’s 10th-best prospect by Baseball America, but after sneaking up on folks in his first two starts last season, he got absolutely lit up. Not to mention he’s already 26 years old. That’s the same age as Tyler Wilson, who showed flashes in spot duty late last season but fanned just 13 batters in 36 innings. There’s also been talk of reliever Brian Matusz transitioning back to the rotation, but that would mean losing a valued lefty option out of the bullpen. Last but not least is Vance Worley. The former Pirate, whom the O’s claimed off waivers in October and who has a 3.86 ERA in 81 starts during his six-year career, is a more ready-made option than Wilson, Wright or Matusz. Snowball score: 7.1.