Dear Nitesh,
There are two issues involved in your query. First one can CEO directly approach Manager's junior. The reply is yes, he can approach.
However, bypassing manager and dealing with juniors directly has its side effects. This approach is violative of the one of the
principles of management that Henry Fayol has propounded. This direct approach dilutes the authority of the manager. If this trend continues then the junior employee may develop closeness with the top boss and it erodes the value of the manager. He/she may get demotivated.
However, in this direct approach by CEO, we need to know two things. Was CEO dealing with the junior all along and Manager joined recently? Does CEO feel little uneasy in dealing with the Manager because of his long association with the junior? If yes, then Manager may show little patience and wait to establish his credibility.
The second point about this direct approach by CEO is about loss of trust of the Manager. CEO could be considering Manager ineffective hence he could be dealing directly.
Notwithstanding either option, Manager may tell junior employee to keep him posted on getting direct orders from CEO. If from above, then let Manager be informed from bottom. After couple of such instances, Manager may ask subtlety to CEO about bypassing him. Manager may bring new ideas or concepts to make his presence felt. Manager may identify the weakness of junior and strike on his weakness at the right time. Manager should not allow his junior to smart under his feet and to do this, if some manipulations are required then he/she should be prepared to play them!
Thanks,
Dinesh Divekar