Participles can describe (and agree with) a noun, but the meaning would be different. The other function of adjectives/participles in the instrumental case is to be a predicative and collocate with a link verb: быть/выглядеть/казаться/... усталым (счастливым, несчастным, .... раскатывающим тесто))) Here it's a part of the predicate, but not an attribute describing Льва Троцкого.