5V digital input on Pro Mini 3.3 volts

Can I use 5 volts on the digital input pins of the Arduino Pro Mini 3.3 volts ATMega 328. I’d be powering the mini with 3.3 volts, but I’d like to connect one of the digital input pins to 5 volts. I’m asking because I want to connect a Pro Mini to an Ethernet shield. I’m hoping the 3.3 volts coming from the pro mini is high enough for the Ethernet shield to see that as high. If so, then I only have to worry about the MISO pin (12), which would be 5 volts coming from the shield going to the mini. If the mini can handle a 5v input, I shouldn’t need to do anything. If not, I could put a voltage divider on that line or a level shifter.