Murphy's fantasy value was low coming into the season as he was coming off a .220/.282/.374 season with the Texas Rangers.
So far he's found a fresh start playing for the Indians as he has ridden a recent hot streak to a .294/.360/.483 139 OPS+ and five homers. His value going forward is dependent on whether he can keep his batting average/obp relatively high and whether he continues to get opportunity to AND take advantage of RBI opportunities.
He'll likely keep the batting average relatively high (.276 career average) and a .308 BABIP indicates he is performing to his actual ability. While I think the batting average is going to stay relatively the same, i'm not quite sold on him being uber-high value going forward as he seems headed towards okay power (~15 home runs) and stolen bases are very rare for him these days.
His most similar player through age 31 is Todd Hollandsworth. Its safe to say that Murphy's age 32 season is going to turn out much better than it did for the 1996 NL Rookie of the Year as Hollandsworth had a 72 OPS+.
Doolittle's value is rising as he seems to be settling into the role of designated ninth inning pitcher for the Athletics. The last couple years he has pitched in relative anonymity but those days could be over for fantasy owners. Although he has a decent ERA (3.13), his underlying numbers indicate that he has a chance to be much better than decent.
His FIP this season is at 1.54 (2.31 for his career), he barely walks anyone and has rung up 9.8 SO/9 in his career. His primary value is of course going to be in saves but he does look to provide likely incremental value for strikeouts, ERA & WHIP.
In one corner, you have an outfielder who hits for a decent average and will give you some (but not excessive amounts of power) that could be good as a fill-in. In the other corner you have someone who just picked up a closer jobs that looks to contribute in saves and has some under-lying statistics indicating that he's even better than what he's shown so far.