野球選手はフライを取る時には風を考えに入れておかねばならない。

。

Baseball players have to take the wind into account when catching a fly ball.

Literal

Baseball-player [topic-は] fly-ball [obj-を] catch-time [at-には] wind [obj-を] thought [in-に] put-[keep-ておく]-[must-ねばならない].

~ねばならない is the classical/formal contraction of ~なければならない, still productive in formal writing. 考えに入れる ('put into one's thoughts,' i.e. 'take into account') is a set idiom built on the にする/になる pattern. フライ is a baseball loanword ('fly ball') — English baseball vocabulary is extensively borrowed into Japanese.