B737 flight crew reported engine malfunction during climb out. Flight returned to departure airport and landed uneventfully.

Narrative

On climb out around 15500 ft we got an oil filter bypass light. We continued the climb and ran the checklist. The checklist directed us to retard the throttle until the light went out. It finally did around 78% and we contacted Mx (Maintenance) and dispatch per the checklist. Our VHF patch was not very good and thus couldn't have a good conversation with Mx. After realizing we were going to be thrust limited and we were going into weather at ZZZ1 we decided to go back to ZZZ. In the turn back to ZZZ the light came back on and we had to reduce the throttle further to 62% to get the light out. Realizing the engine was getting worse we requested priority handling and proceeded back directly to ZZZ. The return was normal until we got to around 7k and intercepted final. At that point the light came back and we had to pull the throttle to around 35% to get the light out. We started the APU as it seemed like that might be needed if the engine failed since the issue was getting worse. We landed without incident; had the fire trucks check us out and proceeded to the gate.