Jermain Defoe will miss Toronto FC's clash against Colorado Rapids.
The former Tottenham striker is carrying a hamstring injury.
"With Jermain, we have to get it right," Nelsen said in reference to Defoe, whose original diagnosis was a "mild" hamstring pull.
"If we have to sacrifice next week (road game April 19 in Dallas) . . . it's a long season and he's probably got something more in the summer (World Cup with England). So we have to take care of him."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball