Instead the Red Sox signed righthander Nathan Eovaldi, with a career ERA+ of 95, to a four-year, $68 million contract.
While the Trade Simulator's net value of a negative $400,000 for Hunter Strickland is surprising, that negative value pales in comparison to Eovaldi's negative value of $26.6 million.
https://www.baseballtradevalues.com/trade-simulator/
BTW, in July 2009 the Red Sox traded Strickland and infielder Argenis Diaz for nine days of Adam LaRoche, who was then traded for Casey Kotchman.