Why is my enemy AI hovering over ground while chasing player

The enemy AI is hovering over the ground when it is chasing me and I am not sure how to fix it. Here is my script (My screenshot that is 1 mb is apparently to large):

 using UnityEngine;
 using System.Collections;

 public class followplayer : MonoBehaviour
 {

 Transform player;
 float f_RotSpeed = 3.0f, f_MoveSpeed = 3.0f;

 // Use this for initialization
 void Start()
 {

     player = GameObject.FindGameObjectWithTag("Player").transform;

 }

 // Update is called once per frame
 void Update()
 {
     /* Look at Player*/
     transform.rotation = Quaternion.Slerp(transform.rotation
                                           , Quaternion.LookRotation(player.position - transform.position)
                                           , f_RotSpeed * Time.deltaTime);

     /* Move at Player*/
     transform.position += transform.forward * f_MoveSpeed * Time.deltaTime;
 }

}