Jackson, a one-time Detroit Tigers starter most recently with the Washington Nationals was thought to be the best pitcher on the market following the Tigers re-signing of Anibal Sanchez. The Cubs were the runners-up in the Sanchez sweepstakes.
The Cubs had reportedly offered Sanchez $75 million over four years but the Tigers were afforded the opportunity to match or exceed Chicago's offer. Detroit did just that, signing Sanchez to a five-year, $80 million deal.
The Sanchez deal averages out to $16 million per season and was widely thought of as an overpay, although one that probably made sense to a team in serious win-now mode with World Series aspirations.
The Jackson deal averages out to $13 million per season.
Considering the talent of both pitchers, it seems the Sanchez deal looks slightly better in retrospect.
Jackson has been worth 10.5 WAR in the past three season compared to Sanchez's 12 WAR.