the end date of his contract is getting close, that's all.
sen had some really good results this year, so I don't think they would willingly get rid of him (if anything, they could just bench him and keep him as a sub / streamer, since he's got a decent audience), but it's really tough to live so far from all your friends and family for such a long time, so he might choose not to extend his contract and move to a BR team, or maybe even retire