One trade that always bothered me was the Paul Konerko for Jeff Shaw trade in 1998. Trading a cost-controlled slugging first baseman for a reliever is rarely a good idea.
How'd the trade work out when viewed through the WAR lens?
1998: Karros 2.6, Shaw -0.2, Konerko -0.3
1999: Karros 5.2, Shaw 0.9, Konerko 2.0
2000: Karros 1.8, Shaw 0.3, Konerko 1.7
2001: Karros -0.1, Shaw 0.3, Konerko 2.4
2002: Karros 1.7, Shaw (retired), Konerko 2.2
From 1998 to 2002 Karros and Shaw produced 12.5 combined WAR for the Dodgers while Konerko produced 8 WAR for the White Sox.
Dodgers win the trade? right? They ended up with 4 more wins.
Well, there's also the issue of salary.
From 1998 to 2002 Karros and Shaw earned a combined $44.9 million.
From 1998 to 2002 Konerko earned $6.8 million.
If LA hadn't made the trade they would have had an extra $38 million with which to try and buy 4 more wins. I think they may have been able to achieve that.
An interesting thing to look at is just how similar Konerko and Karros were during that period (1998-2002):
Karros: 823 Games, 3289 PA, 128 HR, 481 RBI, .274/.334/.457 for a 108 wRC+
Konerko: 802 Games, 3164 PA, 129 HR, 475 RBI, .279/.342/.471 for a 108 wRC+
Hard to get more identical than that.
However, Konerko was more of a DH than 1B man. Karros accounted for 17 defensive runs saved while Konerko was at -8. That leaves total WAR at that time at 11.2 for Karros and 7.6 for Konerko.
Still, that's a trade I'd like to have back.
*Karros, Konerko and Shaw data from FanGraphs.
*Salary data from Baseball-Reference player pages