[kq76]

You say "they". Is the AI controlling substitutions or you? If you have the AI making the subs and they're taking him out, then I'm not sure what you can do. Maybe he's just not as good as a bench player and so the manager would rather put in a pinch hitter? But if that was the case, they should probably start that PH as the DH instead.

Wait... This is a DH league, right? If it's not, I'm not sure you can keep him in. I've never considered keeping a 2-way player in the game in a no-DH league.

I understand you probably have all this set correctly if he is indeed starting as pitcher and DH, but just in case that's not the case, let's cover all our bases...

First, you have to make sure that the checkbox is checked @ League > Settings > League Settings > Stats & AI > General AI Roster Settings > Allow two-way players.

Next, go to the player's profile screen of the player you want to make a two-way player and click on Strategy. Then on the bottom right if the options are greyed out, click on "Lock to Team / Enable Strategies". Then check "Use as a Two-Way Player". If you want them to also bat in the game's they pitch (the previous checkbox only allows them to bat and pitch, but not necessarily in the same game), then also check "Skip DH when pitching".