Nate can be a weapon out of the pen if he can iron out his command to the point where he can at least place his offspeed pitches near the strike zone. The opposition can just sit and wait for mistake heaters because they can effectively spit on everything else. Maybe adding a splitter can at least give the opposition to think about in the likely scenario that Nate has no feel for the offspeed stuff on a given day. It could also serve to disrupt the timing of the opposition when they are gearing up for the heater. Nate still has tremendous stuff as evidenced by a 127 stuff+ overall rating, including 118 for the heater and 140's for both the curveball and slider. I do have a bit of trepidation that adding another pitch to the arsenal of a guy with serious command issues though.
I'm very curious to get an eye on Rodriguez against major league hitters. I recall that the stuff+ system absolutely hates his4 seamer and gives it a ranking similar to Ryu's mid to high 80's fastball. It features very high spin and sit's mid 90's while featuring a bit of a cutter shape, so hopefully this is just a case of an outlier fastball that sort of breaks the stuff+ system. Rodriguez is maybe the offseason's most interesting pickup in that we simply don't know what kind of role he's going to fulfill moving forward. He's being stretched out as a starter in spring, and if he can even manage to become a good back of the rotation arm this deal offers a lot of upside. If his success out of the pen in Japan transfers to MLB he could also develop into a high octane leverage reliever so there are multiple avenues for this deal to pay big time dividends.