Mikey Johnston became one of Celtic’s January transfer window casualties after completing a loan move to West Bromwich Albion. The 24-year-old was a bit part player for the Bhoys in the first half of the campaign, registering two goals and two assists in 12 appearances. Brendan Rodgers detailed the actions he believed Johnston would need to take to establish himself at Parkhead last year. The Irishman stated: “He’s 24, and if you want to play at a club like Celtic in the starting line-up regularly, you have to have robustness, and you have to be mentally strong. You have to be competitive and …