On 13 September 2012, Bateau signed a one-year contract with an option for two additional years with K.V. Mechelen of the Belgian Pro League. Sheldon made his league debut on 6 October coming on as a substitute in the 59th minute in a 0–2 defeat to Kortrijk. On 31 October, Sheldon made his first start for the club against OH Leuven that resulted in a 1–3 loss. Afterwards, Bateau solidified a place in the starting line-up as a centre back and appeared in 11 league matches, including five consecutive starts, prior to the 2012–13 winter break. His consistent form resulted in Sheldon signing a two-year contract extension, on 18 January 2013, keeping him at Mechelen until the end of the 2014–15 season. On 27 April, Bateau scored his first two league goals during a play-off match against Waasland-Beveren that provided his club a vital 2–0 win. Bateau concluded his first season in Belgium with 22 league appearances and two goals.
