That being said, it's hard not to at least be intrigued by the following table. Here's a list of relievers in 2015 who pitched at least 30 innings, had an ERA under 2.00, had a strikeout rate over 11, and a walk rate under 2:
Going back to 1961, only 10 other pitchers have accomplished that feat. Obviously it helps Givens to be at the bottom of the innings spectrum, but it does show how dominant he could be.
There's no one quite like Darren O'Day in the majors, but the Orioles may just have the closest thing to him. Perhaps that's why the O's were so reluctant to include Givens in any potential trade during last season's non-waiver deadline. There's no real way of knowing until we get to see him pitch more.
If O'Day does depart, which grows more likely every day, then Brad Brach may get the first crack at the set-up role. But Givens could easily be thrust into set-up duty as well. Is it ideal to use a 25-year-old with limited experience in the majors (and with pitching, in general) in that role? Maybe not. Sometimes that's what teams have to do when they have limited resources -- in this case, a mid-market team -- and are trying to decide which players to sign to fill a number of holes.
There's a case to be made that the Orioles should trade Zach Britton now, reap the benefits of the increased value of dominant relief pitchers (see Craig Kimbrel), and re-sign O'Day. Britton, O'Day, Brach, Givens et al. is a very solid group of relievers, but even one of Britton/O'Day is still pretty good. If the O's aren't at least exploring a Britton trade, they should be.
If Givens ends up being anything close to O'Day in the next few years, the O's will be thrilled. And even if they don't end up in the same bullpen in 2016 and beyond, at least Givens got to work with O'Day for a while and hopefully absorb what he could.