Projecting Josh Donaldson: what can the Blue Jays expect if they extend him?

The subject of a contract extension for Josh Donaldson was the big news early this week as Spring Training got into full swing, which is quite timely as it’s something I’ve been thinking quite a bit about. Not surprisingly, there seems to be a significant gap between the two sides, and at the end of the day Donaldson is well within his rights to ask for the moon with his recourse being testing the free agent market.

The more interesting question is what the Jays should be willing to offer. Ross Atkins spoke a couple weeks ago of having “a number” and “a clear walkaway”, which is ultimately a function of a player’s projected future production and how the team values that. The second part is a little trickier, but I want to focus on the first part today: taking a crack at projecting what Donaldson is likely to do over the time horizon of a potential extension.

A typical approach, the “quick and dirty” method, is to take a weighted average of recent seasons or current year projections, and then apply an aging curve on the order -0.5 wins per year over a player’s mid-to-late 30s. This is what you typially see at FanGraphs. For Donaldson, that would mean something like 6-6.5 WAR in 2018, declining to the 1-2 WAR range in his age 39-40 seasons

This approach is useful, and has its place as a high level tool, but it’s susceptible to the criticism Donaldson levelled. It uses a completely generic aging curve that does not take into consideration the player or at least specific characteristics. It’s also highly sensitive to the initial season. What we want to do to get a better idea is look at similar players.

Since he fully emerged as a force in 2013, Donaldson has accumulated 3,270 PA with a 147 wRC+ and 36 WAR. He’s played five mostly complete seasons, and has maintained an elite level of production through his age-31 season. Even last year when he dealt with injuries, he was just shy of 500 PA and produced around 1 WAR/100 PA as in previous seasons. Accordingly, my initial screens were for players with at least 2,500 PA from age 27 to 31, and eliminating those who clearly in decline by age-31 or had a major down year.

My first comparison set was elite third basemen in the post-WWII era, players with at least 130 wRC+ and were still playing third base by age 31. I added George Brett to the initial screen (just shy of 2,500 PA) while eliminating the likes of Ron Santo and Sal Bando. That left eight players, and not surprisingly, it’s one heck of a list of players.

Overall, the group is a very strong match for Donaldson. The plate appearances, offensive production and fWAR over their age 27 to 31 seasons match up very closely.

The first thing of note is their age-32 seasons. On average, they posted just over 600 PA (similar to Donaldson’s projection), but posting a 131 wRC+ and 5.0 WAR. Both of those marks are short of Donaldson’s projections, which suggests that the projections might be optimistic on him. And the starting point really impacts a valuation using the “quick and dirty” method. Certainly, there’s plenty of variation, as Schmidt and Brett had monster years in line with their primes. No one was a complete disaster, but half the field had seasons that were good-to-very good rather than star level.

But we don’t want to read too much into one year. We’re more interested in the broader extension horizon, so let’s look a few scenarios. First, a shorter extension (presumably with higher AAV) that would cover 2018-2022, so four additional free agent years. The comp set averaged about 20 WAR over this part of their career, with a low of 14 and a high of about 32. On the positive side, all of the players delivered substantial positive value. The only way this type of deal would happen is if the Jays essentially paid Donaldson like 2018 was a free agent year rather than already having him.

So let’s look at something more likely. A straight five year extension added on his last year of control, covering his age 33 to 37 seasons. Here the outlook is more variable, as the average falls to 18 WAR, but with a 16 WAR median. Schmidt and Jones had 31 and 25 WAR left in them, but Mathews and Cey only had about 10-11 WAR. It’s definitely more of a gamble.

Finally, an extension that covered through age-40, as Donaldson alluded to. That essentially covers through to the end of a player’s productive career, as only Jones, Boggs and Brett played in their age-40 seasons and the latter was done, just playing out the string of his last contract. Despite adding three years, the average and median only jumps by 2 WAR to 20 WAR and 18 WAR compared to the first first years. Jones and Boggs had some decent seasons, Rodriguez delivered a little value, but the other five were basically done.

In other words, even for the elite of the elite, there’s little expected value after age 37. Donaldson can complain about the unfairness of aging expectations, but there’s just not that much for a team to pay for. Maybe they could justify paying an extra $20- or $25-million in total, but it would essentially be a mechanism for deferring salary.

If Donaldson really believes in his ability to age well in his late-30s, the he should look for a shorter extension (four/five years on top of 2018) with higher annual salaries. The vast majority of the expected value a team is playing for comes during that time period, so he’d lock in most of the dollars anyway. And then if he’s still productive at the end of that, he’d still have signifiant earnings power well beyond what a team could justify locking in now.

Overall, I think this is a pretty good group for estimating Donaldson. The major problem is it’s a pretty small sample, and each data point has significant influence, so the worry is the conclusions are not robust. So I built a second comparison set focused just on offensive production. Donaldson has been a plus defensive player, but his defensive metrics have been trending downwards. He should have no problem sticking at 3B in the short to medium term, but it’s likely that his value on any extension will be largely driven by his bat.

This second group consists of players with a wRC+ within a dozen points of Donaldson (135 to 159). This is a much larger set, of 68 players, and once again in aggregate it’s a good match:

The age-32 average was 585 PA and 137 wRC+, which is a little better than the elite 3B group, and closer to Donaldson’s 2018 projection. So I probably buy a slightly better 2018 than the 5 WAR implied by the 3B group. But over the longer time horizons it’s quite similar, with the 3B slightly ahead (130 v. 128 for ages 32-36, 127 v. 124 for ages 33-37, 123 v. 123 for ages 33-40). The 3B group has higher playing time, which makes sense since they were better and/or more athletic than the offensive group that had a lot of corner OF/1B/DH types.

One final thing. Since the screen for that last set of players was just wRC+, it doesn’t account for offensive profile. Donaldson’s defining attribute is power, so players like Rod Carew or Pete Rose probably don’t tell us much. So I screened out low power players to see if it made a difference. The remaining 53 players performed slightly better, about one or two points of wRC+. That is, almost bang on the elite 3B group.

All in all, this gives a pretty good sense of what to expect from Donaldson over the horizon of a potential contract extension. With a production baseline established, in the next part we’ll look at putting some dollar figures together and playing Let’s Make a Deal.