Jalen Rose's Lawyer FURIOUS: Prison Sentence Is 'Outrageous'

Jalen Rose's lawyer is LASHING OUT at the Michigan judge who just sentenced the former NBA star to serve 20 days in jail for his March DUI ... claiming the sentence is an "abuse of discretion."

Attorney Keith Davidson tells TMZ, "The 20-day jail sentence issued today by this Michigan judge is outrageous."

He adds, "Today we saw a horrendous example of judicial temperament and discretion."

Davidson insists Jalen is a "model citizen who has personally donated millions to charity, established inner city charter schools and a medical center in the Congo" and most importantly ... "has NO PRIOR criminal record."

Davidson adds, "[Jalen] was the victim of abuse of discretion; lack of proportionality in sentencing; legislating from the bench & instituting illegal minimum mandatory sentences for DUIs in violation of law. "

"Mr. Rose is examining all of his legal options based on today's events."