Two wrong players in Bochum

Two wrong players in Bochum

An interesting situation occurred in the first round of the German 2nd Bundesliga. Two Ibrahim Sissokos played for the Bochum club. Both players are from Mali, but they are not related. One is a striker, the other plays as a midfielder.
One of the players plays under number 6, and the other under number 9. 
The club bought Ibrahim Sissoko last season. This year, they transferred the second.