A minimal model used previously to treat the collapse of a polymer of molecular weight n in monomeric solvents is extended to polymeric solvents of molecular weight x. This model reproduces the Flory results in the expanded polymer regime with the controlling variable (1/2x - chi) becoming zero at the Theta temperature. In the collapsed region the system shows a "tricritical point", with the polymer displaying a second-order transition at small molecular weight x which becomes first-order for x larger than a critical x(c). Surprisingly, for x and n large and equal, the dimensions approach the Theta temperature value, [R(2)](n) = C(n)nl(2), with only a weak dependence on the value of chi. Recent experiments do show only a weak dependence of [R(2)] On X.