There's good news and bad news when it comes to the Boston Red Sox bullpen.
The good news is they lead the league in WAR (wins above replacement) on Baseball Reference with a 4.5. That's honestly quite impressive, right? Sure, but I think we all know from watching the team that they still have work to do in that department--because it's not all about who can log 3 scoreless innings in long relief. The high leverage stuff against the top-class batters really does still matter.
So what can the Red Sox do about it now? Didn't the trade deadline pass already? And isn't there like no good free agents on the market at this point in the season? Well, as Christopher Smith at MassLive points out, they could get someone prior to the waiver trade deadline which is August 31. Remember, the trade deadline we tend to think of is the non-waiver trade deadline. It's an interesting system, frankly.
What's the problem? Well, Joe Kelly has been trash since June. Matt Barnes has been known to fade in the second half. Tyler Thornburg is a low-leverage guy, as is Ryan Brasier. Drew Pomeranz shouldn't be someone they rely on for anything. The same could be said for Brandon Workman. This is more of a gut-level instinct: do you trust thee guys in high-leverage situations? There's probably a lot of people saying "no". Exactly. Case rested.
We've seen the Red Sox make a couple reliever moves at the waiver deadline in the past. Two that come to mind are getting Billy Wagner and also trading away Manny Delcarmen so yeah, it happens. And if you think about it, a month long rental could be cheaper than a 2-month rental.
The Red Sox have to be all-in on this season at this point; getting another arm is a part of that.