What Do the Numbers Say?

Mark J. Rebilas-USA TODAY Sports

Yes, another post about do we sign a free agent pitcher or go with what we have. Must be the offseason.

Although it's hard to put into practice, I think there's a lot to be said about keeping an eye on the future and not paying for past performance. (Which is arguably what we'd be doing with signing one of the three big SP free agents, as for each of them, there's reason to believe a decline, perhaps even a rapid decline, in performance is coming sooner than later.)

With that in mind, I thought it would be useful to have their projections in one place, compared to our in-house options. Let's first take a look at what PECOTA has to say:

Chris Archer: 3.23 ERA, 3.5 WARP
Jake Arrieta: 3.70 ERA, 2.6 WARP
Lance Lynn: 4.47 ERA, 0.8 WARP
Brandon Woodruff: 4.48 ERA, 0.7 WARP
Aaron Wilkerson: 4.73 ERA, 0.1 WARP
Brent Suter: 4.86 ERA, 0.1 WARP
Alex Cobb: 4.92 ERA, 0.4 WARP

So PECOTA would tell us that if we can't swing a trade for Chris Archer, then Arrieta is the only FA starting pitcher worth looking at for 2018 -- otherwise we'd be better off going with one of our in-house guys.

How about ZIPS?

Chris Archer: 3.27 ERA, 3.10 FIP, 5.2 WARP
Jake Arrieta: 3.67 ERA, 3.98 FIP, 2.7 WARP
Alex Cobb: 3.77 ERA, 4.03 FIP, 2.5 WARP
Lance Lynn: 3.82 ERA, 4.32 FIP, 2.1 WARP
Brandon Woodruff: 4.17 ERA, 4.19 FIP, 1.9 WARP
Brent Suter: 4.41 ERA, 4.43 FIP, 1.4 WARP
Aaron Wilkerson: 4.77 ERA, 4.72 FIP, 1.3 WARP

ZIPS would argue that the trade for Chris Archer would pay dividends in 2018, and also that any of the FA options would be better than what we have. Let's do one more (Steamer):

Chris Archer: 3.49 ERA, 3.49 FIP, 4.3 WARP
Jake Arrieta: 4.19 ERA, 4.11 FIP, 2.8 WARP
Alex Cobb: 4.43 ERA, 4.38 FIP, 1.7 WARP
Lance Lynn: 4.67 ERA, 4.73 FIP, 1.3 WARP
Brent Suter: 4.70 ERA, 4.79 FIP, 0.9 WARP
Brandon Woodruff: 4.73 ERA, 4.68 FIP, 0.6 WARP
Aaron Wilkerson: 4.94 ERA, 4.95 FIP, 0.1 WARP

Steamer pretty much agrees with ZIPS, although it dislikes our in-house options even more.

All told, they agree that Arrieta is the best of the FA options available, and Archer would have the biggest impact for 2018, disregarding the cost of acquisition. It'll be interesting to see what David Stearns decides to do.