Tom Tango has another fascinating question going over at his blog. The idea is to try and figure out what replacement level in baseball means — not on a mathematical level but on a gut level.It seems like many people simply cannot get their arms around the replacement level concept — and I will admit to having some issues there myself. The way I usually think about it is as the sort of player you can easily acquire or call up should someone on your team get hurt.Look at the Yankees:Mark Teixera is hurt, replaced by Lyle Overbay. His WAR this year: 0.2.Curtis Granderson is hurt, replaced by Vernon Wells. His WAR this year: 0.4.Derek Jeter is hurt, replaced by Jayson Nix. His WAR this year: 0.4.Alex Rodriguez is hurt, replaced by Kevin Youkilis (minus-0.2 WAR) who is replaced by David Adams (minus 0.3 WAR).The Yankees tend to get bigger replacement level names, but the concept is pretty much the same whether it’s a once good player like Wells or a lifelong utility guy like Joaquin Arias or a Class AAA guy called up to stabilize things for a good prospect not quite ready for the big leagues. Replacement level talent is what the words suggest – the level of a player you could find as a replacement.But, I readily admit that the concept can be a bit wonky. There are players in baseball who get a lot of at bats who are BELOW replacement level … so how does that figure? Sometimes, a replacement player is actually pretty good, sometimes he is much worse than replacement level, it’s can be a complicated and hard-to-pin down concept.And it should not be: Replacement level should be something that you feel naturally, something that just sort of makes sense without any real thought. This is something that Tango has spent quite a bit of time considering, and he offers a cool way to think about tit.Consider the following four pitchers:Bob GibsonRoy HalladayPedro MartinezNolan RyanNow, here’s the thing: You can have any of those pitchers for their entire career. But you get the career exactly as it happened — there are no exchanges or refunds. You get their strengths and their weakness. You get their greatness and their limitations.So you can have:Pedro Martinez, ERA- is 67 (Gave up 33% fewer runs than league average), pitched 2,827 innings.Roy Halladay, ERA- is 76, pitched 2,721 innings.Bob Gibson, ERA- is 78, pitched 3,884 innings.Nolan Ryan, ERA- is is 90, pitched 5,386 inningsObviously, this is oversimplifying things — but you can see your challenge. Pedro Martinez is the most dominant of the pitchers — not just for his career but he had the most dominant individual seasons as well — but he threw about half the innings of Nolan Ryan. You will have to fill those innings with someone else. But who? Replacement pitchers.What about Gibson against Ryan — considerably better run prevention, more dominant seasons, but there are still 1,500 innings to make up. Again, who will fill the gap? Obviously the answer is: Replacement pitchers.So, for fun, do this little exercise — rank the pitchers you would want in the order you would want their careers. Put your ranking in the comments section.And what you say say something about replacement level. What does it say? We’ll ask Tango.