Learn Spanish (Latin America): El guepardo es veloz; capaz que lo veas correr por la sabana. - The cheetah is fast; you might see him running through the savanna.

With verbs of physical perception like ver (to see) or escuchar (to hear), you can follow them with either the infinitive (correr) or the gerund (corriendo). Using the infinitive focuses on the action as a whole, while the gerund focuses on the action in progress. English almost always uses the "-ing" form for this, but Spanish lets you use the infinitive!

Since there is an infinitive, could I attach the pronoun to it and say "veas correrlo" instead of "lo veas correr"?

Not in this case! While you can normally attach pronouns to the end of infinitives (like quiero comerlo), verbs of perception work differently. Because the cheetah (lo) is the one doing the running, the pronoun acts as the direct object of the perception verb (veas). Therefore, it must go right before the conjugated verb: lo veas correr.

Why is the verb veas in the subjunctive mood instead of the indicative ves?

It is triggered by the phrase capaz que. In many parts of Latin America, capaz que is a common, colloquial way to say "maybe," "might," or "it's possible that." Because it expresses uncertainty or a mere possibility rather than a declared fact, it requires the subjunctive mood (veas).

Quick refresher: why do we use por instead of para for "through the savanna"?