Clayton Mortensen's name comes with a bit of a stigma attached. It's not his fault, but the way he came here will be remembered for a good bit, with the Sox shipping off Marco Scutaro in order, ostensibly, to free up payroll, and then never doing anything with said money.
That Marco Scutaro then went on to have a very solid season eventually emerging as the hero of the postseason doesn't really help.
But the sins of the team are not the sins of the player. It's not Clayton Mortensen's fault that the Red Sox were running on tight margins last year, and it's not Clayton Mortensen's fault that Marco Scutaro was still good. What can be attributed to Mortensen, however, is 42 innings of 3.21 ERA ball, and there's certainly nothing wrong with that.
Every single member of the team who you could possibly have high expectations of entering the season failed on some level. David Ortiz finished on the DL, Dustin Pedroia wasn't his usual superlative self, Clay Buchholz had his disastrous start, and I don't really think I even need to explain Gonzalez, Ellsbury, Crawford (well, more the fools us if we expected anything), Lester, Beckett, Bailey, or Melancon.
That list is long, but as bad as the performance was from the biggest names, the lesser names certainly provided some decent surprises, and the bullpen was arguably the hub of this. Clayton Mortensen may not have been the biggest surprise there, but he was certainly one of them. Called up from the minor leagues in May, Mortensen was utilized primarily as a mop-up long reliever early on, but made his presence known as best he could in limited opportunities. Throwing nine innings in three games, Mortensen allowed just the one run on just six hits while striking out twelve batters. He would do much the same after a month-long trip back down to Pawtucket, finishing June with a 1.20 ERA after tossing six more innings.
For all that Mortensen was able to keep runs off the board early, though, there was definitely some fade as the year went on. August doesn't look so bad on a game-to-game basis, with really just one bad meltdown against the Angels (in a game where they put up 14 runs), but he would not put up a monthly ERA under 5.00 then or in September. He finished the year allowing runs in five straight games, coming out to a total of seven earned in as many innings. Those K:BB numbers, once so dominant back in May, dropped to a solid-but-not-amazing 41:19 by season's end.
In the end, Mortensen may not have really made the final breakthrough that it seems like Junichi Tazawa made, at least not for the Red Sox. It's not entirely clear if there's a place for him on this team given the fullness of the bullpen, especially considering that Alfredo Aceves seems to be coming back for long relief duties. If that's the case, the Sox will have to find a trade partner since Mortensen is out of options. If that's the case, it's going to be a shame to see them drop an interesting up-and-comer, even with question marks, in favor of some more expensive players who really have not pulled their weight.