The loan regulations
Standard Loans. Subject to the provisions of Regulation 52.2, Standard Loan transfers shall only be approved in accordance with following provisions:
53.2.1 Standard Loans shall be allowed to or from Clubs (or, as applicable, clubs) in membership of The Football League, The Premier League, The Football Conference, Northern Premier League, Isthmian League and Southern League providing the rules and regulations of the respective leagues so allow.
53.2.2 Subject to the proviso that the duration of a Standard Loan must be the time between two Transfer Windows, Standard Loans can be for half a Season or a full Season. Any recall clause requiring the early termination of a Standard Loan can only be included in a full Season Standard Loan and this can only be activated during the second (January) Transfer Window. Any other early termination of a Standard Loan must be by way of a mutual agreement in writing (including by way of a recall clause within the Standard Loan Agreement) between both Clubs and the Player but can only be completed after the expiry of 28 days and only during a Transfer Window (but subject to Regulation 53.2.3 below).
53.2.3 A Player whose Standard Loan expires (or terminates) on completion of his Loaning Club's League Matches will not be eligible to play for his Parent Club (where it is a Member Club) in any remaining League Matches in that Season notwithstanding the fact that he is a Registered Player of that Club and that such expiry or termination occurs during a Transfer Window.
53.2.4 Notwithstanding the provisions of Regulation 53.2.2, a Standard Loan of a goalkeeper (but not otherwise) may be subject to a recall clause exercisable at any time. Any recall may only be implemented in extenuating circumstances and with the consent of The League, such extenuating circumstances to be determined in The League's absolute discretion. A goalkeeper shall not be permitted to resume any Standard Loan following the exercise of a recall.
So if Muric has been loaned for a full season it can only be terminated early during the January transfer window Unless see the above bold text but special conditions apply for a GK see 53.2.4 above
Not sure if the PL squad has been registered but the ECL one hasn't