A pitcher in a blue shirt, on the mound, practices his grip before throwing the pitch.
There is someone practicing his craft.
a pitcher refers to someone, practices his grip implies to practicing his craft
exists e1 s1 x1 x2 x3 x4 x5 x6 x7.(n_pitch(x6) & n_grip(x4) & of(x4,x3) & n_male(x3) & n_mound(x3) & a_topic(x1) & on(x1,x3) & rel(x3,x4) & Time(x4,x7) & n_practice(x7) & Theme(e1,x6) & Actor(e1,x5) & v_throw(e1) & (x4 = x5) & in(x1,x2) & n_shirt(x2) & a_blue(s1) & Theme(s1,x2) & n_pitcher(x1))
exists p1 x1 e1 x2 x3 x4.((x1 = x2) & Theme(e1,x4) & Actor(e1,x3) & v_practice(e1) & n_craft(x4) & of(x4,x2) & n_male(x2) & (x2 = x3) & n_person(x2))