With Rangers starters enduring a period of inconsistency down the stretch, Ryan told ESPN Dallas' 103.3 FM's "Galloway and Company" on Monday that he would give the nod to the 26-year-old rookie from Japan.
"It would have to be Yu," Ryan said. "I just think that he's throwing better than our two left-handers. He's more consistent. He's got more variety of pitches that he can show a hitter and he just seems to enjoy those situations and has stepped up in those kind of games, and I really believe that's probably the way to go."
Ryan had favored opening the playoffs with one of the Rangers' left-handed starters, either Matt Harrison or Derek Holland. However, the Rangers have won five of Darvish's last six starts, with the loss coming in the opener of Sunday's doubleheader with the Los Angeles Angels, 5-4. Darvish left with a 4-3 lead after pitching 6 2/3 innings, allowing three runs and striking out seven while walking one.
Holland won the second game Sunday but allowed seven earned runs in the process and left after allowing a three-run homer to Howard Kendrick in the seventh. Holland went just three innings in his previous start, a win over the Oakland A's on Sept. 24, after throwing 77 pitches.
Harrison leads the Rangers in wins with 18 but is 3-3 in his last six starts.
The Rangers need just one win in the last series of the year at Oakland to clinch the AL West for the third straight year. Left-hander Martin Perez takes on fellow rookie Jarrod Parker of the A's in Monday night's game.