"weakened ability" is correct and usable in written English.
You can use it to describe a decrease in capability. For example, "The company's weakened ability to innovate has caused a decline in profits."
The Grizzlies are also expected to test the Knicks – on their transition defense, their weakened ability to rebound and their improved ball movement on offense.
Many of the players also share a genetic risk factor for neurodegenerative diseases, so perhaps deposits of tau are the result of brain trauma coupled with the weakened ability of the brain to repair itself.
A statement by the Treasury Department also announced the formal start of tightened restrictions, under a law passed last year, meant to severely inhibit Iran's already weakened ability to repatriate earnings from the sale of oil, its most important export.
A study in Development and Psychopathology, after controlling for the effects of mistreatment, found that children in foster care have a weakened ability to regulate their emotions and impulses and to persevere when confronted with intellectual challenges; these behavioral problems were exacerbated when they were placed in a foster home with strangers rather than relatives.
Individuals already living on the edge get less information and support, less knowledge of resources they need and a weakened ability to participate politically in the greater society.
This will lead to a weakened ability to repay, creating a vicious cycle that hurts the financial sector and the credit ratings of the borrowers".
Had my emotions weakened my ability to be a nurse?
(A 2007 Supreme Court ruling greatly weakened the ability to do even that).
Three's exclusion weakened its "ability to be a competitive force in the U.K.," he said.
A Nest spokeswoman said industry lobbying had weakened the ability of the organisation to serve low-paid workers.
"The private equity houses left the business laden with debt and that weakened their ability to defend themselves and fight".
